I'd agree with this sentiment, on the backend, it isn't really easier and it's not really harder either. You end up dealing with different problems than with REST (as noted, different types of performance problems, more issues with error handling have been my biggest two).

The frontend developers see the biggest improvements, they have one endpoint to worry about and using a library like Apollo makes things really nice.

Overall, I think the improvements are worth it, especially when working on internal APIs.