I would agree that REST beats GraphQL in most cases regarding complexity, development time, security, and maintainability if the backend and frontend are developed within the same organization.
However, I think GraphQL really shines when the backend and frontend are developed by different organizations.
I can only speak from my experience with Shopify's GraphQL APIs. From a client-side development perspective, being able to navigate and use the extensive and (admittedly sometimes over-)complex Shopify APIs through GraphQL schemas and having everything correctly typed on the client side is a godsend.
Just imagining offering the same amount of functionality for a multitude of clients through a REST API seems painful.
Looks a lot like it's inspired by https://amie.so . They also have a Notion integration, but it doesn't work completely flawless yet – but they are only out of beta since a few months I think.