@Postmodern You write “some” but I think it is many that require participants in AP courses to take the exams.
Just like with college applications, AP test strategy becomes as important as the exams themselves. Some colleges (like Emory) are now reducing the amount of AP credits it students can get. If a kid has 9 credits going into an AP exam period where maximum credits allowed by enrolled college is 12 or 15, then that student can only get a maximum of two more accepted exams. If he or she is taking 5 exams and only two can count, the game changes as that student might want to focus on two or three exams and not focus on two tougher ones at all. Senior year AP exams can be very much the last college admissions “game” these kids play in this process.