I think I would follow the advice given at the end of the material on this topic, and use OpenID for logins where security wasn't a big concern, but not where security was paramount. I can see advantages in not having to create and remember lots of different usernames and passwords, particularly where you may want to login to a particular site once but possibly never again. For example, when purchasing online you are often required to create an account even though you may never want to use this website again. I have found this quite tedious and time consuming, and also slightly worrying if you have to enter name, address and email details, and quite often end up receiving emails from this site whether you want them or not, which does get annoying, especially years after using the site. (Although I guess using OpenID wouldn't really stop this happening). Also, there are enough usernames and passwords to remember every day as it is without constantly adding to them!
I hadn't heard of OpenID before but it is a useful thing to know about, another tool to use or not as you see fit, bearing in mind the advantages and disadvantages associated with using it.