Its notable that you have three chances at a specific card with these slots, but they are guaranteeing that a maximum of one will be foil
The MTG banlist for all sanctioned formats are managed internally by Wizards of the Coast
Later on, Co-Leader designer posted this letter to the Lorcana Discord, which goes into more detail on why the two cards were banned: Dear Illumineers, We are writing to address the recent decision to ban the cards Hiram Flaversham –
These days most decks don't have enough black cards to be able to comfortably pitch to this nor do they have enough reliable card draw to easily stomach the two for one
Of these cards, Curious Homunculus is the clear winner in my book mana ramp that transforms into cost reduction, a more potent interpretation of mana production, is incredibly strong, even if you have to wait a full turn cycle to start taking advantage of either mode
Boros Signet, Promise of Tomorrow, and Darksteel Forge are all great choices