Amd mew is an OG in this franchise, it has been a part of the game since the start and also is the ancestor to every other Pokemon
A 3/3 matters, especially for decks that just want bodies in play
Red-White sucks in Commander for a lot of reasons, but the biggest reason is its the least diverse color combination
Instead, they can play the Universes Within version Cecily, Haunted Mage
For quick reference, Archenemy is typically played as a 3v1 game where all players use Commander Decks and one player, the titular Archenemy, has an additional deck of scheme cards, one of which is drawn each turn
Its a pretty strong package in general, and theres some potential to see the big crab out of control and combo sideboards when the instant and sorcery count is high enough