Rift crystals are earned by playing just like the first game. Their only purpose is to hire higher level pawns, but you earn them when people pay for your pawn or you complete their quests. It’s part of the interplay of players exchange pawns.
Recent Capcom games have all done this where it’s a great game and right on release they stuff a bunch of micro transactions in for in-game currency but you would have to be an absolute chud to buy any of it because it’s so trivial to earn.
DMCV did the same thing with trying to sell red orbs, the primary upgrade currency, but if you didn’t see people complain about it online, you wouldn’t even notice it in game.