In context the video was just a good explanation for the memory concept. Or rather the lack of memory. A session grows rapidly in token usage, because it has to be fed in again and again. The model is not fine tuned to you by usage, it "forgets".
It also explains, why excessive use of such a system needs so much computing hardware and electricity. And doing a little chatting with chatgpt does not do this. But trying to replace a software developer with ai will do that.
You seem to fuss about the word token or the definition. It's just the bits or atoms of language. A chatbot has to operate on those pieces, so measuring the usage of the bot is easiest done by counting how many pieces a session used.