Yes, I'd be worried it was too close to an original and constituted plagiarism, apart from the fact that it takes away the pleasure of writing and composure.

The only reason I sympathised with the chap who's been doing it for an Upwork client is because the pay was so bad, and it helped him speed through by producing a first draft, but then I don't really know how much editing he did, and he's since lost work to people using AI instead. Now he's doing chatbot testing, so I suppose it's a related area that he's interested in. He seems to be enjoying it, so I'm pleased for him.