What I like about punching is the immediacy, especially when songwriting..."Hmm, I want to re-record that phrase. Select track, specify punch area, record, done." If it doesn't work, I just undo and try again.
When I'm writing I use a lot of "placeholder" parts, and while I don't expect them always to be the final versions, I do want them to sound decent. Also when I'm writing lyrics, I'll often replace a phrase here and there. There's no need to get involved in comping when a simple punch will do.
Comping is wonderful for sure, but I use it more with longer parts where I'm going to be making decisions as to which parts are better so they can be combined into a single take. Punching is great for replacing smaller sections - fast and efficient. When songwriting, I almost never comp. I attribute at least part of the speed with which I'm writing songs these days to punching.