I don't see the upside, from a Washington fan's perspective. The 2015 draft was a long time ago.
In the NHL, he's shown very little improvement despite the organization basically handing him the starter's role, only to lose it to Vanecek (who isn't any better) almost every time.
He just doesn't play like an NHL goalie should. His angles are off way more than they should be, and as a result he has to flop around in the crease to recover - which is where the 'athleticism' tag comes from. He has no composure with the puck behind his net, to the point where I'd occasionally see his defensemen actually motion and yell at him to stay in the net instead of going back to play pucks. His rebound control is poor as well, but that's an attribute that I think could be coached up.
He also might be a headcase.