I've worked on two projects so far that seriously considered GraphQL. The first I was involved in from the start, and we seriously thought GraphQL was something we needed, but after looking closely at it we backed off, because it really sounded like a lot of work for no real gain.
The second I wasn't part of when they made the decision, and they decided to use GraphQL and now regret it. It works, but it makes things very complicated. We're a single large team responsible for both the front and back end (in fact, two front ends).
GraphQL seems mostly important when front and back end have separate teams (possibly even at different companies) and the front end needs very specific custom data from the back end.
The second I wasn't part of when they made the decision, and they decided to use GraphQL and now regret it. It works, but it makes things very complicated. We're a single large team responsible for both the front and back end (in fact, two front ends).
GraphQL seems mostly important when front and back end have separate teams (possibly even at different companies) and the front end needs very specific custom data from the back end.