Not sure what other carriers do, but on CRJs, dash 8s and other various small planes with Air Canada, a gate checked piece of luggage will be available to you once you deplane. It will not go to the luggage belt. If you gate check on a small plane, it is not checked through.
On all the larger planes on Air Canada, gate checked baggage ends up on the belt with regularly checked luggage. If you gate check on a large plane, they will check it through to your final destination.
Greg