Jay King made this point in a column today:
https://theathletic.com/2663773/2021/06/21/on-trading-tristan-thompson-marcus-smart-on-point-and-coaching-the-jays-12-celtics-thoughts/
https://theathletic.com/2663773/2021/06/21/on-trading-tristan-thompson-marcus-smart-on-point-and-coaching-the-jays-12-celtics-thoughts/
The Celtics could start Smart there [at PG]. This shouldn’t be the only determining factor in whether they do, but the team has historically been better with Smart at point guard – and in some years much better, according to efficiency numbers from Cleaning the Glass. It should come as no surprise that the Celtics defense has often been elite with Smart at that position. When in that role, he gives them bruising perimeter size and allows them to lean all the way into a defensive-minded identity. In a single season, Smart has never played more than 27 percent of his minutes at point guard, according to Cleaning the Glass, but that’s partly because the Celtics have had such good options at that position.