This is so useful. I'm using it to give entire presentations from PowerPoint where an icon on the slide is replaced with my face. I switch slides, the part of the slide is detected, and the scene automatically switches. This means that I can use the same set of OBS scenes with many different PowerPoint presentations. I do wish that the build included had the OBS Virtual Camera, but it is no big deal to use the plug-in version.
This should absolutely be included in the main OBS source.