BTC will not be the world's currency! The feature that bitcoin is now showing is its value, not its circulation. Because everyone thinks it's going to go up, who's stupid to use it as a payment currency. When its currency is stable, its payment features will naturally emerge.
Many countries don't think BTC is a currency, they think BTC is an asset!
Some other countries think BTC is illegal!
I think if we use bitcoin for an asset, we want to see the price is increase. maybe there will be another coin which more stable than bitcoin so it could be use for payment currency. and for now, it is better to use the benefits from bitcoin which could help us to make money, this is the things that people thinking.