We are in Kansas. There some DE classes that aren’t also AP like Project Lead Way, Econ, and others, but many are the same class. Some give identical credit for AP and DE while others give different credit. It also differs by university what credit you get for each.
Different states have different rules- which can complicate DE if you are looking out of state for colleges (public or private)
Our experience is similar to @ynotgo’s. DE at our local universities allowed our son to remain a high school student and not graduate early. In terms of finding other interests, he did that as well. He graduated with 6 foreign language credits, philosophy credits, spent hours upon hours on independent study. (He owns so many Great Courses titles I don’t even know how many. He spent hours on MIT Opencourseware.) But there is only so much branching out you can do, and there comes a time where the best course of action is forward progress. APs are limited.
No question that DEing at the local universities was the right choice for our Ds. He thrived. Made high grades. (Shocked his professors when he asked them if they would write LORs for his college applications or had to miss class to take the PSAT. 
They had no idea he was still in high school.) And when he was applying to colleges, even a top 40 university accepted all of his DE credit which included 300 level math and physics courses. (ETA: and his DE universities were both OOS from that univerisity. We moved when Ds was in 11th grade, so he attended 2 different universities for DE. Anyway, no reciprocity agreements.)
At Bama it has meant that he can pursue their University Scholars option and earn his masters during his 4 yrs of UG. No regrets. He would have been twiddling his thumbs without those courses in high school.
His sister, otoh, who is every bit as gifted, if not more so, has chosen an alternative path. She is working with private tutors and doing self-exploratory projects like spending a yr researching Shakespeare. It has been easier to provide her those non-math and science experiences.
That would not be possible at our school. The menu of dual enrollment classes is very limited. When my kid took a post calculus math class it wasn’t an official dual enrollment class. With my signatures, the hs was willing to allow her an extra study hall and a campus release in order that she could go off campus to attend the class. But they didn’t give any hs credit or put the course on her hs transcript. So it would have been difficult to do very many college courses. I’m actually not sure whether they would have allowed it if she weren’t a senior. Usually only seniors are allowed to be off campus during the day. But it’s possible we might have been able to negotiate an exception.
In my state, DE is fully funded, so the student pays nothing. Even the books are provided. The only exception is lab fees - I had to pay $40 for my daughter’s Environmental Science lab. DE takes place on the college campus, not in the HS. A student may take any course that has a HS equivalent, which covers most but not all of the lower level college courses. Students can participate in DE at CCs or 4 year colleges and universities if they meet admission standards. Admission standards are slightly higher for DE students than for typical applicants, and at our state’s premier engineering school, DE students are only permitted if they have exhausted all the STEM courses offered at their HS.
Given this setup, I much preferred DE to AP credits for my children. My oldest really wanted nothing more to do with HS after her junior year, so full-time DE was a great option. She spent her senior year on a college campus being treated like a college student. It gave her a chance to figure out how to deal with college coursework and administrative issues while still living at home. (She was shocked that her entire grade for a class came down to 3 exams and a final - no homework, no participation points, no extra credit.) Learning to deal with the different academic expectations before she moved into a dorm and got distracted by college life meant that she transitioned to her “real” college easily. She started college with 29 credits on her transcript. (She purposely kept it under 30 to allow her to qualify for a full tuition scholarship that was only available to freshman.)
My younger daughter homeschooled through HS, so didn’t have the AP option. DE (which was free even for homeschoolers) helped fill gaps in her schedule and also provided her with an introduction to college. She entered her LAC with 16 DE credits.
Both my daughter’s are attending private LACs now, and both received full credit for all their DE courses. Neither girl was assigned general elective credit or required to repeat any DE courses.
I was speaking recently to an acquaintance who is a department head at private university that is ranked in the top 25 nationally. He says that their admission department prefers AP to DE, but couldn’t tell me the thinking behind it.
I think colleges (in general) prefer AP b/c it is a national system- one stop shopping (in terms of evaluating credits etc) DE is clearly different state by state and school by school. Some universities are willing to spend time figuring it out- some aren’t 
Don,t know that I’d ever discourage DE if free. My personal feeling is that high school students should be able to find challenging high school courses. In the system we have, high schools have abdicated their their responsibility by shoving students into DE or buying canned curriculums like AP. However, nobody should skip out on challenging herself to make a point. I am saying, however, that DE rarely delivers the benefits that the high schools say it will.
For my kids, DE lived up to the promises. My daughter’s HS actively discouraged DE, but it was definitely the best option for her. For a lot of kids, the high school environment is stifling. Getting out of the HS and onto the college campus a year early was a huge bonus for my daughter.
DE has also “lived up to its promises” for our kids. But, they have taken their courses on 4 yr university campuses and were in need of the challenge. Students do need to educated about DE b/c policies are not similar from campus to campus.
For example, here is Wake Forest’s DE credit policy:
^ This is the problem both of my daughters ran into: their school only offers DE taught at the high school by high school teachers. I paid for the DE credits but neither daughter ended up being able to use them because the universities they attend have a policy like Wake Forest’s. Most of the DE credits were from a respected private 4-year university too.
To answer the question regarding whether DE is “the new normal”: AFAIK our district doesn’t have a DE option.
So are students with DE credits considered freshman? Are they offered the same scholarship opportunities as students with no DE?
@sax The majority of the time, yes. As long as the credits were taken before high school graduation. 4 of my older kids have graduated with DE credit, anywhere from 18-40 credit hrs.
I have heard of only a handful of schools that have restrictive rules and treat them as transfer students.
Thanks mom2. I had no idea. Son was able to get 52 credits for 12 AP courses back in 06. AP tests cost $72 then so that was an awesome deal.$16.60 a credit hour. Was considered a freshman even though he had sophomore standing. DE not popular in our area back then.