3 mana is a pretty low cost of entry for free tokens every turn
Aside from being a human, which is a very relevant creature type in Commander, Modern and basically every other MTG format, Esper Sentinel is good because it reads: Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays X, where X is Esper Sentinels power. Its a bit like Rhystic Study, but the cost can be far higher if youve got things that make humans stronger or you can put +1/+1 counters onto Esper Sentinel
Giving your opponent access to that isn't always ideal, but you get it first, so I think it ends up benefitting you more often than it benefits them
Arcane Sanctum ($1.50) Important art and only one other foil to compete with, itll hit $5 before the end of the year
I'd have loved to see a combat damage trigger on Snapdax, but maybe the best way to make the most of this scary kitty is to mutate something big, nasty or both