He ultimates at the same rate and draws cards without needing to build around it dramatically, like you might with Vraska, Golgari Queen
And of course, getting a gem mint card is largely out of the players control
This leaves you vulnerable because an opponent can destroy that creature in response and you draw nothing
You get to put a lot of yourself into them, and even if you take a precon deck or you a premade character and modify it to your taste, theres still going to be a lot of yourself in the final product
Perhaps had they known then what we know now, they might just have taken better care of them rather than shoving them in their pockets and, heaven forbid, actually using them to play the Pokemon Trading Card game
It essentially grants additional effects on a card if you exile a certain creature type from the battlefield or your hand