maybe some countries think bitcoin is a payment tool that will replace fiat, because satoshi made Bitcoin / cryptocurrency might be created to aim at creating a digital payment instrument, in an era where technological advances are growing, and why some consider bitcoin is one of the best investments because, it can only done online, whereas if fiat was created for real payment,
The real reason why bitcoin is invented is to make it as a real currency like dollar and euro but since majority of the people are making it as a good investment and never really use it in most of their payments, so bitcoin remains as an alternative currency next to fiat. Crypto will gain more recognition in the next years but replacing fiat for crypto is still very impossible for now to happen.