What I know is that countries are planning to impose regulation on cryptocurrency exchanges but not on cryptocurrencies like bitcoin and ethereum because they already decentralized meaning no one can control it or make some changes in the coins itself. Regulations are good if they are not restrictive or there are too much rules on using any cryptocurrencies. If the aim of the regulation is protect the users and curb the use of cryptocurrencies in illegal means like money laundering and trafficking, it will be good.
To some extent it is good and to some it is bad. the good side is this people will trust it the most because of the back of the government and they will put their money in it, and the bad side is this government will impose tax on crypto earnings, trading and transactions and people will have to pay taxes. For this angle it is not good. I dont want to pay tax to my government.