When you can produce faith in something, that something receives value.   

The thing that one has faith in does not necessarily have to have material substance.   It's substance can simply be the faith in it.   

Bitcoin has no substance except people's faith in it.   Suppose every bitcoin holder cashed in for real dollars.   What would happen?   

As to SpaceX, there is NOTHING of value on the moon.   Even if there is something of value on Mars, how could its value overcome the cost of getting that something back to earth?   

You see, the whole concept is imaginary.