Grealish is told to play like that. Not sure how that's not understood given how many years he's been here. (Not specifically at you - just generally from others and mainly neutrals)
He draws players to him which usually leaves somebody on their own in a better position to shoot. Look at Jonny Boulders's goal against Arsenal, two players rushed out to Grealish which meant he could square to Kovacic who had a free shot on goal.
The sooner it's realised that he's not expected to run at defenders with pace and dribbling, the better. We have Doku, Savinho and now Nunes for that. Grealish offers something different and a lot more composure, cleverness on the ball and retention than those. And it works. Hence the treble winning season.