I've have only ever used a crate for puppies. It seems as much for their safety as anything. Having a puppy roaming around the house, or even jsut a room, unsupervised at night while you sleep just doesn't seem like "good parenting" to me. And as you mentioned it makes it easier for clean ups when there are those inevitable accidents.

Once they learn to tell me they have to go out, I remove the crate. So since you have one who does that, I would save your money and use that crate for the puppy.

If you decide on this route, you may want to start keeping that dog out of the crate NOW, so he doesn't sassociate losing his crate with the newbie and become jealous. You know, "mom MADE me give up my home for YOU!" kind of thinking.