Why homebrew? For me it's simply the joy of creation. I'm lucky enough to have players that find my ideas interesting enough to want to explore what I have in store for them. It's been stated before, but an easy way to get players to want to play in a "foriegn" system is to add plot hooks based around the characters and the world. Give each character something in the world that is connected to them and put the spotlight on each one in turn. I find that does wonders for getting players into the feel and spirit of a homebrew setting.
Oh, I am most definantly a heathen homebrew creator. However, Scarred Lands has no more to fear from me than any other setting that I find interesting. I'll take bits and pieces from everything equally.