The Hasura GraphQL Engine automatically generates your GraphQL schema and resolvers based on your tables/views in BigQuery. You don't need to write a GraphQL schema or resolvers. See How Hasura GraphQL Engine works for more details.
The Hasura Console gives you UI tools that speed up your data-modeling process, or working with your existing database.
The Hasura GraphQL Engine lets you do anything you would usually do with BigQuery by giving you GraphQL over native BigQuery constructs.