It's also fair to use it as a clever dictionary, to find the right expressions, or to use correct grammar and spelling. (This post could really use a round of corrections.)
But in the end, the message and the reasoning should be yours, and any facts that come from the LLM should be verified. Expecting people to read unverified machine output is rude.
I think we havent realized yet that most of us don't really have original thoughts. Even in creative industries the amount of plagiarism (or so called inspiration) is at all times high (and that's before LLMs were available).
Every time I come up with an algorithm idea, or a system idea, I'm always checking who has done it before, and I always find significant prior art.
Even for really niche things.
I think my name Aeonik Chaos might be one of the only original, never before done things. And even that was just an extension of established linguistic rules.