I am not sure if taxes were used by GP for any particular reason; I think the key is that the governments actually forces other to use the currency for transact

I am not sure if taxes were used by GP for any particular reason; I think the key is that the governments actually forces other to use the currency for transactions. So, as long as the govt itself doesn't drastically change the rules, people wanting to sell their time now will take currency. There is no such mechanism for Bitcoin; it's really not that different from baseball cards, original paintings or smth like that in terms of being a store of value; based entirely on others' assumed future faith of its value (compared to any random cryptocurrency I can start tomorrow, or a print of the same painting/card).