The main reason is that Biorhythm as "finisher" cancels out every kind of play that each player has made so far
(If this card is your chosen companion, you may put it into your hand from outside the game for as a sorcery.) Abilities you activate that aren't mana abilities cost less to activate
Flying for evasion, lifelink to swing races, vigilance to play offense and defense, and deathtouch because why not
Whenever a vigilance creature attacks, it doesnt become tapped
Recommended build x2 Magnemite x2 Magneton x2 Magnezone x2 Oricorio x1 Shaymin x1 Sabrina x1 Pokemon Communication x2 Giant Cape x1 Cyrus x2 Potion x2 Poke Ball x2 Professors Research Decidueye ex deck As a Stage 2 Pokemon, Decidueye ex can be quickly set up thanks to the Rare Candy card
This commander also rewards you for stocking your deck full of legendary Zombies, as it creates tokens of them should they be removed