It's a close cousin to poplar - stinks to HIGH HEAVENS when you mill it. A lot of my buddy's saw mill is built from cotton wood timbers. It's prone to rotting but if kept dry it last a long time.
It shrinks a lot so be sure it's milled thicker than you will need it once dry.
I know of boats and skiffs being built of it but I can't think of any great furniture uses - except secondary perhaps.
Edit-
Oh and it spalts readily.