Exactly, and this needs to get communicated in a much louder way. There is too much fear that if their API isn't "RESTful" it some how isn't useful or good.
Sure, an API that is not RESTful can be useful — but there is value in creating things in a way that is consistent with what many others are doing. When you make a RESTful API developers already know how to use it if they have used any other RESTful API — the conventions are the same even though the underlying data is different.
So, I think that the advantage of using a RESTful approach is that developers have to spend less time to get up and running with your API. The tools they have used for others work with yours with minimal changes. More importantly, the thought process (get, update, create, delete on an object) they use when considering how to implement your API is the same thinking they have used for others.