Because it allows you to generate immense amounts of mana and devastate your opponents
In an Un- game, if X is actually infinite (Urza's Fun House is a pathway to many game states some consider to be unnatural), you can assume that every natural result on a six-sided die is rolled infinite times, leading to infinite Clown Robot tokens and infinite +1/+1 counters on Clown Car
I mean, I like all the words written on this Mardu card, but I think everythings trivialized by d20s, which are incredibly easy to roll given the die-rolling cards that exist
Restricting things even further is Radiant Lotuss tap requirement
Vision Skeins Vision Skeins is kind of low impact, but its the only card that does this, so make sure you know it exists
You'll see where I cheated and brought in extra cards