Yes, AI term is used for marketing, though it didn’t start with LLMs, a couple of years before, any ML algorithm was called AI together with the trendy data scientist job.
However, I do think LLMs are very useful, just try them for your daily tasks, you’ll see. I’m pretty sure they will become as common as a web search in the future.
Also, how can you tell that the human brain is not mostly a very powerful LLM hosting machine?