Earlier quoted context omitted.
I use it for summarization constantly. I made iOS/mac shortcuts which call Gemini for various tasks and use them quite often, mostly summarization related.
How do you know its summaries are correct?
You already know that they aren't. Yesterday my wife and I were discussing Rønja Røverdatter. When we were kids it used to have danish talk over, so you could still hear the original swedish sound as well. Now it has been dubbed, and we were talking about the actor who voices Birk. Anyway, we looked him up and found out he was in Blinkende Lygter, which neither of us remebered. So we asked Gemini and it told us he played the child flashback actor of the main character... except he doesn't, and to make matters worse, Gemini said that he played Christian a young Torkil... So it even got the names wrong. Sure this isn't exactly something Gemini would know, considering Rønja Røverdatter is an old Astrid Lingren novel that was turned to film decades ago, and Blinkende Lygter is a Danish movie from 20ish years ago where Sebastian Jessen plays a tiny role. Since they are prediction engines though, they'll happily give you a wrong answer because that's what the math added up to.
I like LLM's, I've even build my own personal agent on our Enterprise GPT subscription to tune it for my professional needs, but I'd never use them to learn anything.