Crypto currency is unstable and unpredictable.
It's actually great to have things unpredictable, it makes it challenging for everyone to remain in the game.
Therefore, if they become a universal medium of exchange, many problems in the economy may arise. And how can you achieve stability?
Bitcoin had been extremely grateful that developers have been doing everything in its interest to keep things going on and on, and as it goes beyond anything in the world and once it gets adopted at global levels, it'll surely achieve the type of people it really needs in order to work properly for ages. As about price stability, do we really need it? No, because it's the natural advantage here for us to speculate on it and give it a value that we want to sell it for.
Of course, the state must intervene here. In addition, support from international banks is needed.
Really, state? Fuck them up, intervention of governments pr any other institutions is really not needed as Bitcoins' invention was to remove these people's hold on us and make us financially free by keeping everything out of their reach. As well, international banks or anything we call as banks are literally not needed in it currently as I believe that P2P is one of the best ways to remove these traditional intermediaries out of the game.