GraphQL is great when your entities are complicated and interconnected with each other. If you just need to get one user object, it's not different from rest. If you need to get user, then 5 of his posts, then 50 of comments for each post and then 100 reactions for each post, all connected by IDs in your DB, GraphQL allows you to do all of this in a single HTTP request, single SQL query and with 0 lines written by backend developer.
(This example is pretty silly, but I have very similar and not silly examples that I just can't share because of respect for my employer's NDA).
(This example is pretty silly, but I have very similar and not silly examples that I just can't share because of respect for my employer's NDA).