Why?! So I could search by the type of your Pokmon instead of the name. #6 Not a great card - the only utility I can see is if we get a supplementary supporter/stadium that specifically allows you to search/recycle this card or an Enamorus that can augment this card via an attack or an ability
Often times there are restrictions on this choice most often non-land
Choose a Background (You can have a Background as a second commander.) Whenever a goaded attacking or blocking creature dies, you create a Treasure token
Overall, Amethyst, Ruby, and Steel are more focused on attacking while Amber, Emerald, and Sapphire are more supportive, but each can be used to make interesting combinations and people can experiment with seeing what strategies work with their personal play style
As of now, its a good Ability that works well with the high-Energy metagame, but not with the low reliance on effects of attacks
Master Ball mirror foils are not guaranteed in a box, instead you may get 3 Pok Ball mirror foils