Normally, when an enchanted creatures leaves the battlefield, Auras attached to it will go to the graveyard as a state-based action
In terms of non-Trainer's Pokmon receiving alternate art treatments, one standout Pokmon is Electrike, who appears to be standing at attention in the grass...or popping a very strange squat
If you are primarily looking to complete your card collection, the choice is irrelevant
Hence Gold Rush is a filler combat trick
If a monster is Normal or Special Summoned to your opponents field, while this card is in your Monster Zone (except during the Damage Step): You can Fusion Summon 1 GMX Fusion Monster from your Extra Deck, by shuffling monsters from your field, GY, and/or banishment into the Deck
It ensures your card is shielded from bends, dings, and moisture during its journey, which is key to getting that positive feedback you're looking for