Because the OS already includes a home screen. When CyanogenMod ships with a processor, I'll be upset about paying for that, too. I'm not holding my breath, however.
I happen to think this particular launcher is a gimmick, but it's clear that they put work into it and that it's very different than what Google ships.
Right, but if you are looking for a different one it means that you need/want something different than what's provided and satisfying your need surely must have some value to you.