The fundamental question is whether enough merchants will accept it in exchange for valuable goods and services that people want. A currency is as valuable as the tangible benefits you can trade it for. It seems unlikely that it will replace the major systems of exchange, nonetheless, I still hold a small amount of my portfolio in bitcoin denominated assets because you never know. Twenty years ago no one could have predicted the impact of the internet on the banking system. Hell, ten years ago most people were still reluctant to use the online banking services offered by their financial institutions. And now we are at a point where a cryptography based ecurrency is the content of this discussion, which seems to be evidence of the validity of the concept. It's just a matter of whether it will catch on.