I think Engvall has a lot more "utility" as a bottom-6er. But for Edmonton, i can see why they probably see more usefulness out of Puljujarvi if he can get back to at least vaguely producing as a Top-6 coattail rider, where he's probably a better fit for them than Engvall would be.
But for the Leafs, Engvall seems more useful as a defensive presence, PKer, etc. People need to stop acting like Puljujarvi is suddenly going to have a growth spurt in his hockey brain and morph into something he isn't. He's a big, straight line player who plays the game with his head down, blinders on, and very little real awareness or vision on the ice. That's not changing at this point.
Seems like a swap that doesn't really do much for either team. Both probably better off keeping "their guy" and just rolling with the frustrations, unless they can add something to get a bona fide upgrade in that spot/role.