I do not want regulars to sign up and then have to login every time they want to comment because it can be hectic - even with the “save password” feature. Its only a blog, so why should they have to login?
There are many reasons why, the most important being spam prevention.
I dont mind adding them as members manually as the list grows, i just dont want them to sign-up or login. Is it possible to hide the process from visitors?
No. They would still need to sign in with a password.
UPDATE: Can’t EE check the email address of each posted comment, see if its on the “safe members” list and auto-approve it if it is, otherwise mark it for moderation?
This isn’t a built in feature. It would require a custom add-on. Feel free to leave a Feature Request for it.
With registration it prevents a person from having to enter their info each time. What you describe would require a person to enter at least two pieces of info every visit: Name, email, website, etc… Whereas a registered member returning to a site has to enter zero information. They just comment and go. Plus registration allows a profile which means you can add avatars, sigs, and other profile information that might make your visitors feel more at home.
Though the main benefit I see is that registration means returning visitors don’t need to do anything extra to comment. Every system is going to have its pros and cons. For EE what you describe can’t be done out of the box though a custom add-on could certainly accomplish it.