On the topic of privacy, the reason to use an LLM to write is stylometry. If I use my own voice to write anything of significant length, enough personal mannerisms will come through, so that I can be identified by my writing. If someone were to do something subversive, and wanted to be anonymous, that's one more thing to do to hide your tracks.
Just make sure to use a local model if you're really serious about this since there is no guarantee the cloud models can't not won't add watermarks to the output.
