Basically every group of humans across space and time have created some kind of money to exchange between them.

Given that now we have a sound money, it would be a great candidate to use it on Mars.

Paying to someone else when both are on Mars would be basically the same as doing it on Earth, and they would also be able to send and receive BTC from Earth to keep some reserves there.

It would be a bit like how lightning works, and Mars would be seen as a node I think.