Look again at the original post: "Bitcoin won't work with Mars". For the L-1, that statement isn't wrong until we find a way to use quantum binding for near-instant information transmission.

Why would a hypothetical colony in Mars to mine? Well, because they don't want to trust Earth not fucking everything up. Or because they simply want to be able to obtain Bitcoin without having to buy it from Earth.

Would it be better to have it in orbit than in any planet surface? Sure. Even better if it's a Sun orbit closer than Earth, but that's not what was being discussed.