I've recently found that it can be a useful substitute for stackoverflow. It does occasionally make shit up, but stackoverflow and forums searching also has a decently high miss rate as well, so that doesn't piss me off too much. And it's usually immediately obvious when a method doesn't exist, so it doesn't waste a lot of time for each incident.

Specifically I was using Gemini to answer questions about Godot specifically for C# (not gdscript or using the IDE, where documentation and forums support are stronger), and it was mostly quite good for that.