I just can't be bothered with fiddling with config files and installing little bundles and packages for every functionality.
While this is obviously a matter of taste, I do like vim's minimalism in that you start off with a simple core with sensible defaults and just add any features you want (I use tcomment, command-t, and fuzzyfinder for switching buffers - that's pretty much it, my .vimrc is less than one page). I found vim much easier to get into than emacs (which I'm currently using for most heavyweight coding sessions) where the defaults are (imho) not as sensible and you have to dig through tons of stuff that comes bundled with it, instead of understanding everything from the beginning and building from there. Of course, it's great to be able to extend emacs with elisp to do any stuff you feel is missing, and I've generally felt it easier to integrate the whole dev experience (minus the browser) into it than with vim - but such usage was of course never in harmony with vim's philosophy in the first place.
On top of that the whole "language of editing" and combining noun,verb,adjective commands, etc... doesn't really appeal to me because I'm too visual when I'm editing code. I can't stop to think about the right semantics about what I want to do, I just do it visually.
Like the rest of vim, these things just become muscle memory - you will completely stop thinking about what command to use after a bit. The reward is getting all those micro-level text editing tasks done with fewer keystrokes, minimizing the time you spend typing and therefore the disconnect with the thought that preceded the typing. I think this dynamic is really great when you get into the zone and want to let stuff flow out with as little neuromuscular obstruction as possible :P
I think the vi/vim editing model is a genuinely important contribution to text editing technique, much more so than vim the program, but of course you can use vim keybindings in lots of other editors and IDEs and still get the core benefits, assuming the most important vim-powers have been implemented.