You have to tap those tokens to use them, so it does limit your ability to use things like Treasure and Clue tokens, but does give you the opportunity to keep everything open until your last opponent's end step to start using Baylens abilities
Thats useful in and of itself, and while we went out of our way not to include the Sanguine Bond + Exquisite Blood combo (you should have them both in your deck), having one of those effects on a Creature is useful
This is offset with the Harrowings, where Valgavoth emerges with a fresh body
You can use the mana produced by Brotherhood Headquarters's last ability to cast a spell with freerunning even if you're not paying that spell's freerunning cost
Thanks in part to Patrick Chapin ninth-place finish at Grand Prix Charlotte, Grixis is probably the best color combination in Modern
They care about modified creatures, and its fairly easy to make a good army and attack again between +1/+1 counters and cheap equipment