A friend of mine works in advertising/marketing guy at the director level (Career ad guy), for big brands like nationwide cell carriers, big box stores etc, but mostly telcom stuff I think, and he uses it every day; he calls it "my second brain". LLM are great at riffing on ideas and brainstorming sessions.
Or is this someone who needs writing but can't do it themselves, and if they didn't have the LLM, they would pay a low-end human writer?