I think the point is less these particular terms and more the general responsibility to know and use the accounting terminology properly. Sam probably has a dozen examples of financial terminology errors, of varying seriousness and intent, and startup models, by definition, are going to raise still more questions. Sam can't possibly lay out a definitive vocabulary -- the applications of these terms is always dependent on the particular business. He can raise a flag that founders have to take this stuff seriously.

Whether this is exactly the best post for that is maybe another question. It definitely raises the question of how, exactly, founders without any accounting are supposed to navigate this stuff. Accounting is a language of its own, whose conventions make sense once you understand the various problems it must solve, but absent that knowledge it is very easy for people to make innocent but very important mistakes.