Well now that the team has been eliminated, I really hope BB gives Stidham the last two games. Literally nothing to lose (at this point, losing games only "helps"). I get you keep playing to win at all costs while you still have a chance to make the playoffs, but now that that's officially over, it ought to be time for Stidham. Especially if they don't think Cam really is the guy for the team next year. Which, god, I hope they've determined is the case.
I still think Cam can be a really good NFL backup. He can provide some unique things off the bench, and there are definitely worse backups in the NFL. If he's willing to be that guy, there's still a place for him I think.
As for the "there's no such thing as a game day player", we know that's not always true. Allen Iverson hated practice and didn't even give it a try, but come game time, man, electric. The NFL is littered with players who don't even participate in a fair number of practices (to take care of their bodies maybe) but play really well during games.
Maybe he just SUCKS in practice and shows absolutely NOTHING. But if that's so, honestly, he shouldn't even be on an NFL roster. That they're keeping him on board says they haven't totally given up on him. It's night and day playing in practice and playing in games. It's entirely possible that Stidham is better in games than in practice. We will never know unless, you know, he gets a chance to play.