on services offered, then its up to someone if he would use up his crypto to avail those service or buying up something or rather would opt out always with fiat and save up crypto for the future.
Its a matter of choice and these decisions will really differ for each person.
But as much as I love crypto,,, it is not possible to opt out of fiat at all. And I bet you very few people are able to do that. Even those who claim to live purely on crypto actually what they did is bought a house and a farm (thinking of that Dutch guy who sold everything for Bitcoin) so they are self-sustained. Still need fiat to pay bills!
Lucky if you do able to purchase things directly with crypto but we know that adoption isn't really still on the global scale for you to make transactions from time to time
which would result that you will still need to convert from time to time to make up those common purchases like your living expenses etc.
Majority are holding it and treat it as a store of value.