I never used it. It looks like people mainly used it for animations, I am not sure what kind of interactivity it allowed. It seems that the program didn't support actionscript.
If somebody wants to do animation and then export it to a video then tools like adobe animate and adobe after effects are still better options, although cavalry[0] looks really cool as well.
These do not really have the interactivity that moos.app gives you though.
[0]: https://cavalry.scenegroup.co/