It also combos with counter decks and cards like Doubling Season, giving it incredibly high stats
+6/+6 worth of stats spread across three creatures and Vigilance is going to be enough to enable attacks on a whole lot of boards, between the stats and the fact that you can still have the creatures hang back to block, which really matters in a race
His ceiling is likely to be $30 with peaks at $35, but Id expect him to sit more in the $15-$20 range like Thassa, God of the Sea
Llanowar Visionary Three mana
Cards such as Doomskar Oracle, Iron Verdict, Behold the Multiverse, and Ravenform can all serve to advance your plan while delaying the opponent
Tasha's concept is certainly fun and powerful, especially in Dimir where this sort of steal your stuff, play it later strategy is the norm