1- People buy Bitcoin because it makes them profit from it
2- Bitcoin makes profit because it makes people buy it
It's a circular argument, and creates a perfect closed system, no other "product" can make it, in the center there is greed moving this perfect circle
It's not a good thng. That circular argument is the basis of a speculative bubble. It is a positive feedback loop, which means it is unstable and it is guaranteed to eventually fail.