Reason 1. He's best at point guard. Thomas and Fultz ahead of him on the depth chart, means extremely limiting Minutes for his best position in the floor.
Actually he plays almost all his minutes at one or the other of the wing positions. This allows Thomas to play off the ball; and Rozier is more effective mostly off the ball. Smart gets minutes with Bradley, too, though Avery generally takes the opponent pg on D.
Reason 3. He's a liability on offense. He still can't shoot and can't finish at the rim. This is unlikely to change.
He's a plus on both sides of the ball. Offense is more than shooting.
He had the fifth-most minutes, per game, on the team. He gets crunch-time minutes. Looks like Brad values him higher than the average poster here - the naysayers might take a step back and ask themselves why that is.
Hate to rain on the parade but Hayward doesn't make sense to me.
He is not a plus on offense. Does that mean he's not valuable? No. But lets not get silly.
You seem sure of yourself - or at least enough to think that
I'm being silly. And I'm not sure what makes you so sure, so I don't know what to address about Smart's game. I'll just point to a couple of things.
First off, he was not a plus on offense until this past year. He clearly grew into his new role, with increased responsibility running the offense, and despite the uptick in turnovers he created a lot more good shots than previously, moved the ball at another level from previously.
He upped his own rate of free throw trips (per FG attempt), which also helped the rest of the team get into the penalty earlier; the team free throw rate increased as well as his own.
I could go on - Marcus does a lot of non-box score stuff, has a super instinct for spacing, creates space, throws ahead on the break, runs the offense so that Isaiah can play off the ball, etc., etc...
This is basketball, not HORSE. It's a team game, and Marcus helps you win it.