Does it gain that much in this instance? Probably not. Commenting on intent is actually a nice way to put it, and one habit that I'm trying to break is commenting on mechanics. I've written a number of scripts for people who are not Perl-savvy, and they come back with questions on how this or that works. So for a long time I started commenting on every single regex on how it works -- because that's what people were asking about. These people are general C/C++ programmers, so I didn't get into the habit of commenting code like your first example, thank dog.
So you have a very good point, and I'll add your reading suggestion to my list of books. I have some good habits, some not so good. I knew when I posted this that I might have comments about the style -- which is really what I want. Nothing like critiques of bad practices to break the habit.