There are still many doubts but one fact is proving that Bitcoin is not a bubble. That fact is time. Bitcoin was developed almost 10 years ago, and we all know that no bubble lasts for 10 years. There have been also doubts is Bitcoin mining a Ponzi Scheme? Cryptocurrencies are offering legitimate service to the users and the core activity are differs from Ponzi Scheme, so answer is no. Cryptocurrencies are the future of the online payment method and they are becoming more and more popular from day to day. Before Bitcoin, which was first cryptocurrency, there were some tries of creating digital currency but the main problems was to stop users to spent same money more than once, or so called double spending issue. This problem was solved with Bitcoin\'s blockchain technology which relies on the mutual consensus of the users within a block, which is base of the entire crypto community today.
Cryptocurrencies are developed as a decentralized currencies and that is number one reason why governments are not accepting, there is no way that governments or any other institution can control and monitor market. Adoption rate, demand and of course price will go up if governments accept Bitcoin as a payment method, because conservative people will now have more trust to this online payment method since the government accepted it. Governments are still not accepting Bitcoin and others cryptocurrencies so they are still in the grey area. But things are changing and we can see that some countries are considering to accept Bitcoin. For example Russia announced that they would accept Bitcoin, Japan is the first country that recognized cryptocurrencies as asset which could be a big step forward. To make a resume, governments are not accepting cryptocurrencies because they are threat to the fiat currencies, not because cryptocurrencies are not legitimate.