- There's nowhere to return Page to if it's from the Black Market. You can't Ambassador something that came from the Black Market. Page cannot return anywhere, it cannot leave your deck.
-If we follow pst's idea, this means that I can infinitely use my Page to generate Treasure Hunters. Can you imagine a game where only one player has a Champion, and all five Warriors? That would be stupid. Stupider than a Curser or anything else overpowered in the Black Market.
-If we follow what Donald X was saying before, you have to do both - you have to return, and you have to get one. Therefore a Black Market Page does nothing. You spent $2 on a cantrip, good job. I'm much more comfortable with this, particularly since there is precedence for certain cards just being useless when they're from the Black Market.