The two accounts is a bit different than maintaining a separate admin account in development.

The main reason for the two accounts is to help reduce the risk of drive-by attacks (where you hit a web site and an exploit automatically fires, taking advantage of some security weakness in the browser or a linked app, such as Adobe Acrobat Reader) and emails which effectively do the same thing.

Your non-privileged account is used for email, web browsing, etc., and if it has any admin rights, it's only over the workstation. Therefore, other systems can't be infected with the credentials. That would require administrative rights on those systems, which is what the second account is for.

With the different accounts in different environments, they are all admin accounts. Just one works for dev and one works for prod and dev never has the ability to work in prod.