Yes, an interface view in Denodo will throw an error if it does not have an implementation view.
Interface views are a special type of derived views that consist only of a definition of fields and a reference to another view. Interface views allows teams to work in parallel, for example developers can start working with mock-up implementations while architects can create views that access real data sources.
So, coming back to your question, I would say yes, it is a good practice to define a temporary implementation views that return mock data while the actual implementation is in process of development.
For more information, you can refer to the Virtual data port VQL guide on [creating an interface view](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/creating_derived_views/creating_interface_views/creating_interface_views#creating-a-new-interface-view-implementation-tab) and [defining an interface view](https://community.denodo.com/docs/html/browse/7.0/vdp/vql/defining_a_derived_view/defining_an_interface_view/defining_an_interface_view).
Hope this helps!