Since Bitcoin is a digital currency and highly volatile i.e. it's real value changes so fast that if we're paying it as general transaction it would change in value in no time hence governments are still watching and thinking of the future of Crypto as a legal currency. And as some countries have legalized Bitcoin as a mode of regular transactions Bitcoin will soon become a legal tender in India and other countries.
I don't know, I think that the volatility would be reason not to use it as a currency for daily payments and such. It's too hard to measure the value of something if it keeps changing like this. Standard fiat currencies are lucky to see 2% a day, while these cryptos see 20% or more. It's hard to pay for your groceries accurately if the value of your money moves so much.
And India is moving in the opposite direction these days I thought. They're trying to ban the banks from using crypto because they're afraid it'll escape taxation. India has been quite strict on its people about tax obligations, and bitcoin is one more way that they are tightening the screws.