Its clear the designers thought that putting card advantage on the commander meant they could lower the card advantage pool in the 99
Sapphire Medallion can be particularly strong in multiples, building towards a Capsize-lock endgame (bouncing two or more lands a turn on their end step to keep forward progress going without risking anything)
It's removal, card flow, dodge 40% of removal and dorks and boosts to power for the stuff
We also got to see the other two commanders from the set, and though they're boring humans (boo) they do have some fun effects
As one half of the aforementioned Gisa and Geralf, Gisa is arguably a more effective commander on her own when it comes to filling up your board with the undead and having an on-board way to sacrifice creatures is always a welcome ability
Katilda, Dawnhart Prime is Cryptolith Rite but for Humans, and with the added benefit of an attached mana sink