Both fair points.
Poirier is a pocket striker who fights on toughness, although I will say he's improved leaps and bounds. I don't think he has the pressure game to beat Diaz though.
I don't agree with the submitted better grapplers than Diaz. You can argue Chiesa and Bendo. But straight up grappling Diaz is much better than Pettis. Also he only tends to be out grappled by guys bigger than him, mainly welterweights
All and all I think this fight comes down to which type of Diaz shows up. We shall see, it should be a fun one