Opportunity costs matter in Commander and fitting a repeatable Proliferate effect into a Land slot is often easier than dedicating another spell slot
They have 12 or 13 cards instead of 15, and their card distribution is pretty complicated: 1 art card (5% chance of a signature variant) 1 land (15% chance of a foil land) 6 connected cards 35% chance of 5 commons, 1 uncommons 40% chance of 4 commons, 2 uncommon 12.5% chance of 3 commons, 3 uncommons 7% chance of 2 commons, 4 uncommons 3.5% chance of 1 common, 5 uncommons 2% chance of 6 uncommon 1 showcase variant 2 wildcards of any rarity 49% chance of 2 commons 24.5% chance of 1 common, 1 uncommon 17.5% chance of 1 common, 1 rare/mythic 3.1% chance of 2 uncommon 4.3% chance of 1 uncommon, 1 rare/mythic 2.6% chance of 2 rare/mythics 1 rare/mythic 1 foil of any rarity 1 token/ad card with a chance of being a card from The List You basically sacrifice the boosters ability to be used in a Draft for a chance at multiple rares

Card Name Mana Cost Type Legendary Creature Human Monk Rarity Rare rules Text You may play an additional land on each of your turns.Zell Dincht gets +1/+0 for each land you control.At the beginning of your end step, return a land you control to its owner's hand
Boo hiss, throw the bums out
That being said, Im not a huge fan of this card