I love watching Randle when he's having a good night because he's an old fashioned back-to-the-basket player.
He's a very poor fit for the Celtics. I'm not sure that he can do his part in a switching defense, and the Celtics switch everything. He also is not a scoring threat from beyond the arc. He can stand out there all day and no opposing center is going to follow him out there.
He might be able to bang with Embiid a little, but I'm not sure that makes him worth the money.