SLE is just a marketing tool that has zero bearing on admissions and does not resemble a day in the life of a West Point cadet one iota. The purpose of SLE to reach a broad diversity of students who might not have much exposure to or consider a career in the military. It does enable attendees to open their candidate profile and complete a CFA if they wish (but not mandatory) as well as see the garrison if they have not seen it before. Because it is just a camp, “chances” are based on available slots. However, your chances are best if your profile describes a person who is less likely to consider an academy than the bulk of applicants the academy typically sees and you apply early while there are still spaces. It is not an honor to attend SLE any more than it is an honor to attend any other summer camp. Remember, most appointees do NOT attend SLE and attending SLE is not counted in the Whole Candidate Score (WCS) used to determine appointments.
So, apply if you want to spend a week at the fort, but don’t lose a wink of sleep if you don’t get a slot due to space restrictions; it won’t affect your application one whit. Our son, who is a cow (junior) at WP, didn’t even apply because a) he wasn’t interested in the camp program and b) he didn’t need to spend any time at WP to know he wanted to go there.