we don't need to regulate cryptocurrencies but regulations can be also helpful with the adoption and growth of them or they can be restrictive and even prevent the adoption altogether. in the end it will come down to what they are regulating and how. for example if it is regulation of exchanges and if it leads to a more secure place where people can trade with less risk that would be a very good thing.
its a good idea to think there is a proper regulation among cryptocurrency, and it doesn't mean it is required to be implemented. i agree with what you are trying to say, besides it is also one of the factors that will help the digital currency grow and according to you it will lead to mass adoption and avoid higher risks among users.
Since bitcoin is under a decentralized system and no one governs it, We should implement physical regulations or rules for bitcoin. The advantages of bitcoin towards anonymous transaction is being taken for granted by the criminals since there is a low fee for every transactions. The government must legalize digital currency with utmost monitoring and orders.