And it's much easier to understand, at least for a beginner.
--Steven M. Bellovin, http://www.cs.columbia.edu/~smb
I've been teaching routing protocols for a long time, and I almost always start with RIP for people who don't know what "protocol" means.
If you start with OSPF or IS-IS, you invariably get caught up in things like "what is 'link state'?" or "why does Shortest Path First take that path when it's 'longer'?" Plus any "Internet" engineer needs to know about things like hop-count before they can truly understand BGP.
Also, I usually include reasons to use RIP in a production network. They are few and far between, but RIP has properties which could be considered "features" when compared to other protocols.