It's Morpeko V / Lillie's Pok Doll, my favorite deck of the pre- Rebel Clash format
Like most Pokmon cards, the value of Shaymin 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 (Destined Rivals)
The upgrade in prize cards is hard here because we cannot OHKO a Dedenne GXwith Victini VMAX, and they typically run more Dedenne GX over Crobat V in that deck
Often the engagement then actually gets in the way: you end up ticking off specific tasks within a match, rather than playing the game itself for its own good, and only come back for extrinsic rewards: skins, XP, packs, or whatever else
With a Stuffy Doll on the battlefield, Fury is basically a Fireblast, allowing us to deal four damage to our opponent for free by exiling a red card, while Shatterskull Smashing turns into a weird pseudo-Fireball attached to a land