I'm in this boat as well. I don't even consider him a serviceable backup. He played well and completed his ducks in a victory against a 2-win team that quit on their coach, so I sort of get the excitement from fans that have never seen him play before. But, If this guy ever has to come in for 6 or 7 games he might win one or two. Maybe.
Anyways, after the QB problems and heat the FO took this year, I fully expect them to carry 3 QBs next year -- and they absolutely should. So if Barkley is going to play the 3rd string/mentor role at QB I think its a good deal.