I think you and I have different idea of what API docs are. I think that good documentation for usage is a great idea, but not all projects need formal API doc

I think you and I have different idea of what API docs are. I think that good documentation for usage is a great idea, but not all projects need formal API docs, because not all of them intend for the classes in their project to be used as a library. I agree with you that if your code intends to be used as a library, you should provide API docs. And, if you expose a service then you should probably provide API service documentation with examples. I'd add also that usage examples can sometimes go much further than API docs to clarifying things.