Very simple, people are randomly selected bitcoin for the security purposes. Since bitcoin is safer rather than any other form of money so people are getting motivated for using bitcoin now a days.
If every government allows it as a currency, then it would be more friendly rather than cash.
It's very easy and practical to use bitcoin, but if the government uses it as the official currency, it will become a global threat to fiat as it happens at rate of China currency exchange declining, But I feel bitcoin has an important role in world civilization in the future where all the conventional things will be displaced by technological era.