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'd still be worried that your solution might get FST, and the probability was not the "intended" one.

Secondly, it does not measure the skill of an individual properly. For example, a middle rated participant (CM, Expert) would like to make the probability of AC as high as possible(to avoid FST), they might think that current probability is not high enough. So they spend more time looking for better one. While some low rated participant(pupil, specialist), wouldn't care about probability that much, because they don't have much rating to lose if it FSTs. They could write some solution which "somehow" gets AC, while that middle rated is still looking for better probability. Note, that I'm not talking about high rated people(Master, GM, etc...), I mentioned middle and low rated ones only.

What's your opinion about this? Comment below

And please don't be ratist, this is my secondary account.