In order to make both of them playable, they offer buffs to more than one of these class creature types
Your opponent doesn't play anything meaningful on their turn and simply says "Pass." You say, "During your post-combat Main Phase, activate my Insolent Neonate." You discard the Imp, dredge 5, and reveal two Prized Amalgams and a Narcomoeba
These mechanics can help you shift the power dynamic by either forcing your opponent into challenging a certain character or by giving your character more of an upper hand when they're the one on the attack
Can you identify the fake cards
Because Take Inventory is still on the stack as its resolving, that spell card isnt in your graveyard and wont affect the number of cards you draw
There's also a consideration for commanders that give your opponents more choices to make, since it adds to the interactivity of the game