He's fabulous and versatile, making this a great card to pick up if you're looking for a consistent way to repeatedly draw cards
It was printed in a recent set and it's already made it into a Masters set
Maybe I'll need my spell points later, so why would I spend them willy-nilly
I can definitely understand people not putting Yawgmoth, Thran Physician in their top five list as its only played in one deck, which isnt a dominant player in the metagame either, but the card makes the archetype and there arent too many good mono-black creatures in Modern right now
Theres a lot of interaction between the different effects going on, and a few things to keep the commander from being shut down (hopefully!) to keep the engine turning
Player A vs Player B - On the play or on the draw, B can get Trinisphere out before A can play Thassa, completely locking them out since their 2 lands cannot produce 3 mana