It would be really cool to use Xrm.WebApi in Channel Integration Framework because the Crud-Methods in https://docs.microsoft.com/de-de/dynamics365/customer-service/channel-integration-framework/v2/reference/microsoft-ciframework-v2#crud-operations-apis
are a joke compared to the possibilities in Xrm.WebApi (eg retrieveMultiple records or calling actions).

Also Xrm.WebApi already exists therefore why inventing a second api that does the same things in a more limited way instead of using the proven functionality.