When does GraphQL make sense for internal API design, considering it adds some complexity?

Hey everyone, I've been thinking about our internal API stuff lately. We usually just use REST, and that's been fine. But I'm wondering if anyone's had luck with GraphQL for our own internal services. I get that it lets clients ask for exactly what they need, which means less junk data. Still, it feels like getting it set up and teaching teams how to use it can be a big headache. So, are there times when GraphQL's good points really make up for all that extra work, especially when we're talking about things like caching and how it talks to our databases? Or is it really just better for public APIs, where lots of different apps need different things?