Isn't a short comment a much quicker method to get why something has been done that way instead of having to check git log? Also, if you rely on git log for that, don't commit messages become unnecessarily long and detailed?
Another point is that people tend to write awful comments anyway.
This. When we talk about stellar teams with stellar writers both in programming language and english, it seems nice to throw comment here and there. But when I look at what we do at work, I just... want to s{//.+$}{}, because comments there are A) misleading, B) senseless, C) grammatically awful, D) obsolete. Today almost everyone can be a programmer, but only few know how to explain things in short text at right place. You have to be writer to do that.
The best way to test a comment is to turn it into code and test it as code. Or, in more modern way, make a neural network that parses comments and check if these apply.