Well, even if it is free, you're still saving processing cycles and memory by using the hack, whereas otherwise you would need to run StyleXP all the time. It's probably negligible, but why bother with a program when technically it's already built in? Eh, whatever.

Hell, anyway. Skins aren't too much of a pain for me anymore, I use the extra stuff like Rainmeter and Rocketdock to spruce up my desktop. Finding the right skins and designs is what's a pain.