I have some reasons for that, if you have any doubts please comment below.
Firstly, you can't be sure whether your current solution is correct or not. I mean, how can you know if a solution with AC probability of 0.12345.... is going to pass? How to know if that's the intended solution? And even after getting AC you'll be very worried that your solution might get FST
Secondly, it does not measure the skill of an individual properly. For example,