At first glance it looks like a crap idea - but I gave it a go a while back and got one decent song out of it. I was quite surprised to find that a method of writing a song would work - normally they emerge through my conciousness.
Might be a useful thing to do to get over temporary block, even if its not something you want to do on an ongoing basis (I gave up after a couple of goes due to lack of time....). Plus all the advice given above seems pretty sensible too.