No because if you dont do that you have to involve more engineers anyways to build the REST endpoints and keep modifying the rest endpoints.
GraphQL is also default restrictive (i.e. exposes nothing). You don't need to add engineers to make it restrictive.
In Startups typically:
-> Frontend changes most frequently
-> Backend "utility functions " changes less
-> Data model changes the least
Without Graphql your "backend" ends up needing to have a lot of work and changes because it is constantly needing to be updated to the needs of the most frequent changes happening on the frontend.With GraphQL the only time you need to update the backend is when those "utility" functions change (i.e. 3rd party api calls, etc) or the data model changes.
So you end up needing substantially less backend engineers.