Is it bad if I don’t submit my AP test scores after taking an AP course?
No. It’s not bad because the AP scores are not part of any formal admissions evaluations that I know of. So if you have taken the AP exams and have done well on them and want to put them on your common application and list them then it’s fine, but if you have AP scores that are not great, I wouldn’t put them on there anyway. But the reality is kids who are good testers on the SAT or ACT almost are always good testers on APs, so those scores align.
Do you think the AP tests and SAT Subject Tests are of equivalent importance?
They are similar but AP exams are a little longer and more involved since it covers basically the entire year’s worth of work. It is probably more comprehensive and more reflective of your level of achievement than your subject test results.