1. Remember they can only be taken in May. All but the best colleges give credit for them, and they are probably the equivalent of the typical freshman survey courses in all but the best colleges. Even when they don’t produce credits, they may allow you to place out of a class. Passing some will convince even the best universities that you are capable of doing college level work.
2. If your goal is to pile up credits, consider the CLEP exams, which cover more subjects and are easier but are almost never accepted at the top colleges. Unlike the AP, they do not includes essays and can be taken at any time during the year.
3. Both CLEP and AP can be taken regardless of whether you took a formal class to prepare, or simply worked your way through a basic textbook and learned on your own. As such, they are well suited to a yeshiva student who wants credits without having to go to college. They also allow one to skip introductory courses, which tend to be dull. Also having AP (or CLEP) credits can convince a school that you are qualified for college even if your transcript says otherwise.