Hm.

[Dopplers? Sephiroth sips his coffee. If Jaskier can't tell the difference then that isn't his problem.]

I suppose you might encounter them here. It seems they corral all new arrivals to this hotel.

And yes, that can be used in place of money. It bears a unique identifier linked to an account, so a record is created of each purchase. The bill is paid later. Evidently by the guilds, for now.