I think regulation has good and bad effects in my opinion, because if it is the same as using what is already there (centralized), it is the same as regulating it, while it is made for decentralized, no one regulates it and is free.
but I think the application of regulations is also good for preventing unwanted actions, but yes at least there must be appropriate rules so that these regulations can be agreed by all parties.
I dont think regulation has any positive impact for crypto users. Cryptocurrencies are meant to be used as free-from-third-party control currency and imposing regulations limit their scope. So, cryptocurrency regulations have negative impact in my view.