The problem with most crypto compared to regular money is that it's often seen as an investment. However, one of the most important factors for a currency that is used in everyday transactions is stability and predictability. Money is supposed to ease trading goods and services as a universal middleman. It's not supposed to make someone rich who invested first.
Of course there's also inflation and deflation with regular money but as soon as that's getting out of control, it typically leads to serious economic issues.
From my perspective mails are federated. If I want to explain federation as a concept to someone I always use mail as an example because everyone can write to everyone independent of the provider, you can selfhost it easily, you could move from one company to another (if you use your own domain), protocols are all FOSS.
So at least it's an open and distributed system. What would be missing for it to count as federated?