Isn't this similar to Apples initial idea with the first iPhone? Everything would be a "Web App"
And a vast majority of the apps for the platform used it for UI. C/C++ was generally only used for games ported from iOS to webOS, or when writing a custom plugin for some capability not provided by the service architecture.
C/C++ was allowed, but definitely not chosen "more often than not" on webOS. The UI for a vast majority of the apps was HTML/JS and using Mojo.