Hey Abhijit,
The credits do not get consumed unless queries/mutations are executed. Having an unused running backend costs nothing. You can be at peace about that.
And regarding working offline, we are working on the import/export features. Also, the live-loader will be available with the GRPC support. All of these are coming soon…
EDIT: HTTP/2 is now live on Slash GraphQL
EDIT2: Import/Export and GRPC support is live.