This is just terribly inefficient removal
The cycle is finally complete, and while Temple of Epiphany will certainly make a splash in Standard, I would say that for the short term at least it will be more impactful in Modern
Allowing players to pull supporter cards from their deck and use them immediately, it tilted whole games in its favour - and because of this Tapu Lele became a highly popular, fairly pricey Pokmon card
And if you need to grab a few choice upgrades
Mana Crypt (Kaladesh Inventions Series) The most valuable Magic card not on the Reserved List, Mana Crypt is valuable for similar reasons as Mana Vault and Sol Ring: it can easily add a lot of extra mana to the mana pool and enable some explosive early plays in a game
1 Trainer Most of us never bothered to learn the actual game from which Pokemon Trading Card Game gets its name, but if you did, and got insanely good at it, you might have a shot at getting a No.1 Trainer prize card