I think that traditional Fiat currencies will have no real value in space. As they are grounded with principles and agreements that were established on - earth.
Whereas, with Cryptocurrencies, the sky is not even the limit - space just might be though. I mean, think about it - if you’re in space, how much more frictionless can you get with being able to just send “coins/tokens” or ‘Credits’ as they might be considered from other popular films made in the recent years. I truly believe that Crypto Currency in the long-term will be the future of money, but like any major shift that will disrupt our way of life mass consumer adoption BUT ALSO education will be imperative.
Because people fear things they don’t know about, or are uncertain of - they may resist this change for a while, however just as smartphones have become a part of our everyday lives, cryptocurrencies will someday become part of our everyday lives as well. That is, unless you can envision an alternative where people who are doing business in space are trying to do a Bank transfer via ACH or Wire. It’s not going to be as likely, whereas with the many benefits Crypto provides - it’s far more likely.