I'm absolutely fine if the world at large doesn't use Bitcoin. People who understand the value of it will continue using it. And the fact that bitcoin is used for illegal purposes marks it as a success, rather than a failure. You see value in governments, regulations and monetary systems controlled by central banks. I see value in the absence of those. I think Bitcoin is an enormous success in that it gave people who value the latter an instrument to actually exercise their beliefs. No one is forcing you to use Bitcoin and no one ever will and that is the best thing about it.