From my experience you have to do that anyway if you have a custom data model. Usually the administrators who are defining a CMS model are also the developers

From my experience you have to do that anyway if you have a custom data model. Usually the administrators who are defining a CMS model are also the developers consuming it. Editors need to get trained in the CRUD interface of that model: the UI and the implications for the frontend. This is completely orthogonal to the CMS or whether it is headless or not. Strapi has an interface and semantics that are very clean and conservative, I assume for this reason. It being headless removes complexity and allows it to be more minimal and focused than a vanilla Wordpress installation, which can definitely help in that regard.