If it's the last game of the year and the Chiefs are one win away from winning the division, and Alex Smith and Chase Daniel are both hurt, I would want Ricky Stanzi as the starting QB instead of Tyler Bray. At least for this season. Bray still has a long way to go and is far from ready to take the field when the games mean something.
That being said, that's not much of a reason to keep Stanzi over Bray. You simply do NOT risk Bray getting picked off the waivers by another team before you can fit him onto the practice squad. If he shows even a bucket of spit's worth of potential to play QB in this league, it will be seen in his second year and second full offseason with the team.
It sucks that Daniel is such a turd, but I think the San Francisco game proved that his mobility does make him a better asset to the team than Stanzi/Croyle's tendency to stay in the pocket. If you're stuck with two shit backup QBs, I guess you go with the one that can run.