This makes them highly sought-after by collectors
For example, Strionic Resonator can copy your enter the battlefield abilities of cards with initiative like Caves of Chaos Adventurer Since youll be using cards like Xanathar, Guild Kingpin to play cards from your opponents, theres a slight chance that you run into cards that can venture into the dungeon even before you get the initiative, (maybe you snag a Nadaar, Selfless Paladin, for example)
I mean, its not a bad card, and its mechanically a good card for your decks, but the mechanics arent a nice fit, and adding Mirage in front of it doesnt really work for me as a way to run it here
Collector Boosters often catch heat for being too expensive or having poor quality control
this makes it playable in more situations, and worth the extra mana cost
We aren't psychic like Mew, but for that price, it seems like a steal