The Conclave thing is awkward because IC you are handing over one item, so OOC handing over two is also “wrong”. And then I may spend the next 2 hours stressing about getting my physrep back, because anxiety does that. Personal opinion: I don’t think it’s too bad, the real immersion killer for me is miming and just gesturing handing over or (to generalise to more situations) doing a thing. Any physrep of approximately the right size I can gloss over, including a card for a mana crystal.
I think it would be nice if the crystals were more prominently used in rituals though, that doesn’t have the same concern about getting physreps back.