Common law. Do no harm and honor your contracts. Thats all. Legal system is a fraud entirely. Fiat will be irrelevant soon enough. Btc doesnt evenhave to be the coin. It is slow and public on protocol level, ln has its issues as well (watchtowers). People can make any type of money they want. Like mcafee said, ice cream vendors could make an ice cream coin. Btc hodlers want btc to be everything, but other projects work better in different use cases