This sort of copying has been on Mew cards before and was all used effectively
This is good in that it simplifies the game, eliminating side-decking (altering your main deck between matches), but it does mean you can get blindsided by one-turn-kill decks, troll decks, or bad luck
Created by Satoshi Taijiri, Ken Sugimori, Junichi Masuda Current Series Pokmon Video Game(s) Pokemon Red and Blue, Pokemon Yellow, Pokemon Gold and Silver, Pokmon Crystal, Pokemon Ruby and Sapphire, Pokemon Sapphire, Pokemon Diamond and Pearl, Pokemon Platinum, Pokemon Black and White, Pokemon Black and White 2, Pokemon X and Y, Pokemon Sun and Moon, Pokemon Sword and Shield, Pokemon Scarlet and Violet, Pokemon Winds and Waves, Pokemon Legends Arceus, Pokemon Legends Z-A First Film Pokemon: The First Movie TV Show(s) Pokmon First TV Show Pokmon
Jirachi Prism Star, Latios Prism Star , and classic support cards added utility