Because when I hit Win in Windows 7, a bunch of other 'start menu' functionality comes up that I don't need or want.
BTW who said anything about search?
You did. I don't recall saying the word 'search'.
The point is that you choose the 'start menu' because you want to start something. If it is something I use regularly, I'll pin it. If not, then it's easier to 'search' for it using Win-s that to bring up the start menu and walk the various folder structures within.
Clutter is confusing.