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.
I agree, it depends on the kind of regulation we see and to which persons or businesses those regulations are targeted, regulating exchanges that deal with fiat seems like the right thing to do since fiat is still within the jurisdictions of governments but trying to regulate cryptocurrencies as a whole is something I do not agree because once governments start doing that and realize people comply they will keep adding more regulation to the point the market will be very similar to the fiat economy.