Second, because you dont choose the creature to return until resolution, you wont get completely daggered if someone takes out your best one in response
That being said, in decks like Atraxa, Praetor's VoiceAtraxa, Praetor's Voice, Pir, Imaginative RascalPir, Imaginative Rascal, Vorel of the Hull CladeVorel of the Hull Clade, or other Proliferate decks, this is another option to go alongside Astral CornucopiaAstral Cornucopia, Everflowing ChaliceEverflowing Chalice, and Pyramid of the PantheonPyramid of the Pantheon
Like most Pokmon cards, the value of Umbreon-GX depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Hidden Fates Shiny Vault)
If you get lands, well, that's what we were talking about: you'll be able to play extra lands with cards like Oracle of Mul Daya and Escape to the Wilds, and then your commander lets you sacrifice them to draw more
Unfortunately, those Energy must be in play