It's a common rhetorical device, especially for politicians. I don't think it's a smoking gun for LLM-ness at all.

The "not A but Z" thing and variations thereof was pretty common before LLMs. The noticeable thing about their usage of it is they're trying to use language meant to take the reader from something they might genuinely be confused about to a surprising conclusion, and using it in a way that's entirely banal. It relies on distance between A and Z, and genuine possibly of either. Humans tend to have way better intuition about what is surprising to other humans, and don't make insane mistakes like LLMs do.

Rather than have "Z" be self-evidently interesting, the LLM need to tell us that it's not "A". Except no one thought anything was "A" in the first place, and the "Z" is barely a "B" let alone a "Z".

This also goes for couplings of three short descriptors ("Simple. Intuitive. Seamless.") and summations ("the important part to realise is:"), bullet point lists, etc. All techniques to say: here's the important part, here's the bit you should listen to.

This all being said: the tweet smells like ai to me. Wtf does he mean by sword