I guess though, why not just use something like contact paper, and have it permanently affixed to your desk? I've even seen teflon topped contact paper, which I imagine would make a VERY nice mousing surface.
You *can* do that, but it only gives a very specific type of texture (what's referred to as "fast" on many gaming mouse pad lines, for obvious reasons). While this is wonderful if you like to make full arm gestures with your mouse and keep the settings at fairly low resolutions, it's not always quite so nice if you're trying to make more precise movements, since there's really no tactile feedback to the mouse as it moves on a very smooth surface.
This is where the texturized (is a words I swaers) mouse pads are so nice. It's a very consistent slightly (or very) rough texture that gives a nice amount of precise control as you're moving the mouse, so instead of feeling as if it's gliding across an oiled pan and will just keep going if you let go, it feels like you can tell exactly where you're going to be able to have it stop.
It has more to do with your body chemistry than your mouse. Especially given where the damage is. Some of us are what, in the Mac community, are called "pitters" -- the aluminum on palm rests of Mac portables is pitted by our body chemisty.
I'm not saying the advantages of a mouse pad don't exist for people, just that one of your reasons doesn't seem to be one of the advantages.
Yes, it's something to do with some people's sweat glands apparently, I've heard of it before. I think Vittra is right, though, it actually *is* a good reason to use a mouse pad, because depending on how you hold your mouse, you may have fingers dragging along the surface under it. It's also another reason to use a wrist rest (other than possibly helping prevent carpal tunnel--yes I know that can be debated, but if your wrist would otherwise be on the desk, a rest is going to be better generally ime--which should be plenty reason enough).
If you start having issues with contact paper you've put down, it's a lot harder to just pull it up and replace than a mouse pad with a rubberized bottom is. And *good* contact paper (super teflonized--shush I claims as a words toos--, etc) can be nearly as expensive as a (cheap, but even the good ones can be had on sale now and then) mouse pad. Of course... if you wanted to get a surface (teflon contact paper/etc) a support (cloth/etc) and a non-moving base (rubber/etc) and make a ~custom~ mouse pad, then comparative cost would probably be the last of the issues. Also... pics =P
Also, while contact paper and similar material will generally do the same, a mouse pad may be better for your mouse than a desk surface (especially if you use your desk for more than just writing-ish things, it would't surprise me to hear that some of you solder/etc at your desks =P ) for wear on the mouse's teflon feet. Yes those can be replaced, and no it's not terribly expensive... but neither is a mouse pad, and imo replacing the mice feet is annoying by comparison, especially if you're picky about duplicating the factory-new feel.
^.^ I'm not campaigning to get anyone to use mouse pads (or especially these, since I've never tried them), it's VERY much a personal thing imo, just like keyboard switches, but that's some perspective on reasons you may want to try one if you do use mice. Now, if you're using mice as a power source instead of a HID, you probably want a pad for those too, but a different type and for different reasons D: (eww)
