Whats the harm?
Here's the harm: you have a problem with how a page is being rendered. You want to get from the html page back to the original php that generated it. oops - you deleted all the clues that would make such a traceback straightforward. Before 1.3 there were a much smaller number of comments and it was quite tedious to work backwards.

It doesn't buy you any additional security *and* it's going to make it more difficult to resolve problems.