If I would lend a fellow Jew a cryptocurrency such as Bitcoin, Cardano, Dogecoin, Polygon, Etherium, etc. would there be a ribbis issue?
Do we look at it like lending someone a dollar which there would presumably be no ribbis regardless whether or not the US dollar deflates in value? There is a cryptocurrency line "One Bitcoin is always worth one Bitcoin" which is designed to imply that it is always the same.
Is it even halachically recognized as a currency?
Would things change as cryptocurrency becomes more widely used as a currency?
There are major differences between the various cryptocurrencies. Do they all have the same laws?
If he would try to pay me back in a different cryptocurrency or in dollars/stablecoins, should he pay me based on the value at the time of the loan or at the the time he is repaying me?
If the service he is paying me back with takes a 2% cut, can he pay me back 2% extra so I get the correct amount amount in the end?
I am aware that there is no way of knowing whether it would go up or down in value, so that may make things better.