graphql-compose-mongoose with Typescript without extending Document

I was interested in using the library because i found it very handy in terms of translating Mongoose Schemas to GraphQLObjects. I was blown away by how good it works but i noticed something. In models that we use Typescript interfaces it complains if I do not use the Extends Documents in the interface.

Is there any reason why we should use the extends Document when the mongoose Documentation recommends against that?

https://mongoosejs.com/docs/typescript.html