If your team's offense isn't what it ought to be, having a couple shot erasers on your roster certainly doesn't hurt.
For the Boston Celtics, who have struggled to score consistently this season save for a handful of players, the fact that Robert Williams and, to a lesser extent, Jayson Tatum, have been excelling at making other team's shots disappear has provided exactly that sort of defensive boost, especially recently.
Robert Williams is averaging a league-leading 6.