I'd sit Smart for the rest of the Summer League. Clearly feeling good about his 3-pointers, he's playing hard defensively... done quite a few good things running the offense. Let him finish off the Summer League in this high and go carry it into Training Camp.
Let's avoid risking injury as well considering how hard he goes.
Hes young and working on his game. I would play him the rest of the games.
Considering that he played on every single game he was healthy for last year, and considering that he's looking to playing heavy minutes this year, I don't think playing him a lot more in Summer League would be all that beneficial. He'll still be working on his game as the SL team practices, etc.