To me this conversation has never been about whether Joe is starting or not, it's who he's playing with and how much he touches the ball. Joe is best when he gets to touch the ball. It makes him more active on defense and also more aggressive as an off ball shooter. If he doesn't get involved he becomes disengaged on both ends.
When Joe starts, he's usually replacing Conley or Mitchell. Obviously he's going to get more of the ball in the starting lineup, but he's also going to be a main ballhandler when the other player is resting. There's a reason why the Jazz have been able to perform so well when someone has been out, it's because Joe gets a bigger role and Joe is really freaking good when he's involved. Even though Quin may not see it this way, I think he's on a different level than Bogey, Royce, and JC. He should have the first priority to finish games.
So for me it isn't about whether he starts or not, it's how we keep him engaged and have enough touches for him. You know what I'm going to say next....