Says the guy who probably uses the GPS (one of the most visible application of Relativity) on his phone every other day.

Like we don't already have enough problem with trolls on other sites, we now have them on HN. Sigh

Relativity is hugely useful for scientists and make predicted with extreme accuracy.

So it's a theory, but one could say that it is much more useful than Bitcoin.

Btw, Bitcoin also works based on mathematical theories. If someone were to prove P = NP, Bitcoin doesn't work any more, because I can now steal all your money. The current belief is P != NP, that's why people trust bitcoin, and crypto in general. But it's still a theory.

A theory that makes verifiable predictions is one that "works". Relativity fulfills this criteria.