What do you actually ask at office hours?

Might seem like a dumb question, but I've been reading of ways to maximize GPA. People always say go to office hours and compare it to one on one tutoring. Though I can't think of any valid reason to go.

Take a math class for instance, if I don't understand something, then I simply look it up! It may be minor concept I've missed, or an entire unit. In any case, there's always information available online or through posted lecture notes, and showing up to a professor to ask for readily available information would likely be perceived as lazy.

The only time I've ever gone to office hours was to ask for a proof or logic behind a theorem in differential equations, so that I can build some intuition, however I was told it was out of scope of the class. I assume the response would be similar for other classes if I had a similar question.

So it's kind of a catch 22. There's no point of going to office hours for something trivial, as I can easily and quickly learn on my own, and anything non-trivial is out of the scope of class. But it feels like I'm probably missing out on an edge I could otherwise have.