Unless you are having unreliable connections, then no, there's no benefit. If you are getting drops from your wireless, or it's slow, then yes. You could then put a wireless router in your house, then you would have a lot better reception.
As far as supplementing, well when you are on, you have to use one connection or the other. Can't use both at one time.

Scott
http://www.AAApcMechanic.com