bitcoin cannot replace currency in the world because price is not stable.
currency should be more stable.
you may reply me. currency is not stable also but you should think
USD currency price is up and down 1-2% in 1 month.
bitcoin price is up and down 20% in 1 month.
what will people think if they just change USD to bitcoin then their money down 10% in 10 minutes?
bitcoin can become stock but cannot become currency
Bitcoin is made to be a global currency and not as stock.
Why is bitcoin so volatile?
Because bitcoin is in a very VERY young stage. The system isn't final yet. There are lots of updates to be made in the future that can determine if bitcoin will continue to be the de-facto of cryptocurrencies or not. Not to mention that we haven't achieved global adoption yet.
The USD has been around since forever. So common sense should tell you that it will be stable compared to crypto that hasn't even been around for more than a decade yet.
Do your own research.
Adding to this really good answer, currency doesn't have to be stable to be currency. Let's look at a extreme example, look at the Venezuela's currency, a lot more volatile than Bitcoin.
It's just a matter of waiting until the software follow it's own rhythm, it will eventually happen. And we better have a lot of coins in our pocket when that happens.