This is just writing; terse maybe and maybe not grammatically correct, but people write like that.

It's not just terseness, it's the rhythm and "it's not x, it's y".

In fact, the latter is the opposite of terseness. LLMs love to tell you what things are not way more than people do.

(The irony that I started with "it's not just" isn't lost on me)

	▲	wk_end 8 hours ago \| parent [-]
		> (The irony that I started with "it's not just" isn't lost on me) But an LLM wouldn't write "It's not just X, it's the Y and Z". No disrespect to your writing intended, but adding that extra clause adds just the slightest bit of natural slack to the flow of the sentence, whereas everything LLMs generate comes out like marketing copy that's trying to be as punchy and cloying as possible at all times.