I agree with your thought. It actually depends on the complexity of your requirements. If you want complicated grading mechanisms, I believe there are still very little options outside complicated LMSes like Moodle.
If the requirements are comparatively simple or if you plan to use Tin Can as it is today. I believe there are simple to use options available. You could also look at some amazing tools that work along with WordPress like GrassBlade xAPI Companion and LearnDash. And GrassBlade LRS an LRS installable on any PHP/MySQL server.