The AD-T, as of right now, does not provide any extra benefit compared to other methods of completing Gen EDs such as IGETC. The AD-T does have some benefits if applying to the CSU system because it does give students priority in CSU admission.
The Economic Pathway webpage (http://admission.universityofcalifornia.edu/transfer/preparation-paths/economics-majors/index.html) states:
"If you are working on an Associate Degree for Transfer (ADT) in economics at your community college with the goal of applying to CSU as well as UC, there’s a lot of overlap in coursework. Here’s what you need to know about the differences between what UC expects and what CSU requires for economics transfer students:
The UC pathway expects the full introductory sequence of single variable calculus; CSU doesn’t.
CSU requires statistics. While the UC pathway does not, some campuses may require it post-transfer. Please note that if you take statistics at the community college, it may not count towards the major at UC. Check ASSIST for details on course transferability."
I’d advise that you stick to IGETC (http://admission.universityofcalifornia.edu/transfer/general-education-igetc/igetc/index.html) along with completing your major preparation courses.