If you're helping to troubleshoot, test, or debug the site, you're welcome to create a secondary account to keep a Member-level account around for testing purposes. I did that not long after I got contrib status. It's about the only real reason to have/need a duplicate account here.

I have my secondary browsers (FF and Chrome) use that account instead. That way, if I need to pop into my Member-level account to check something out, it's only a matter of opening a browser instead of having to log out and in several times each time.

I don't use that account for anything else. (All the histories for it are 0). I make it a point to not use it actively for anything other than to browse the site when needed.