As a decentralized currency, Bitcoin's development is not subject to excessive government restrictions or influences, while the cryptocurrency economy is subject to peer-to-peer Internet protocol monitoring.
Cryptocurrencies have not been widely accepted by businesses and consumers, and their prices now fluctuate so much that they are not suitable as payment methods.
It's hard to say Bitcoin is an illegal asset because Bitcoin was never sold through an ICO or any form when it was first launched. What the government can do is to tax every profit people make transactions with Bitcoin because it is considered a commodity.