The weakness of Griselbrand is that if you are too far behind when you make him you have to wait for him to deal damage before you can risk drawing cards and in this situation you are going to get wreaked by the right removal
Maester Seymour starts off as a , but he has a dangerous Monstrosity effect, and also grants a creature you control X +1/+1 counters, based on his power
Im not sure everyone really understands why so much of Magic Twitter, Reddit, blogs and podcasts tended to critically latch on to Michael Majorss statement in the announcement that the Preordain unbanning is also part of a goal to give something back to Blue-Red Murktide, as if B&R should never be about meta-making
This land gives you a way to bring those pieces back and keep your strategy alive even after removal
Sometimes it can be a matter of just a tiny ten HP that stops you from taking a knockout making any kind of damage-modifying Tools are always some of the best in any format
This is all the more reason to ensure you take a look at value when trading or pricing cards, as rarity does not necessarily equate to value