I'm not so sure about their utility as a tool for critical thinking, though that might be just because I've spent most of my life training my brain to do that sort of reflection and argumentation for me. That's obviously not the norm, so I guess if people can find utility in anti-sycophantic roleplaying LLMs to achieve a mode of thought to which they're unaccustomed, then perhaps that might be good... But mainly:

so that I know the lingo to search for it myself

Is exactly how I use it besides writing small scripts for me.

I think of LLMs like intuition rather than intelligence: they're incredibly stupid and wrong and incapable of reason, intention, or thought. But they're a vague and inaccurate amalgamation of all writing on the internet and that can be useful for doing remedial tasks or getting a rough direction to go in.

Prompting a subject can bring up associated keywords, paradigms, and frameworks niche to domain experts which can greatly accelerate my ability to know what to search for and how to think about the questions I have.

They're damn near useless at answering them though, of course... But it helps me orient.