No, actually it isn't. Multi Riffs were rejected by forum members as a regeneration tool in the thread "Unfreeze/regenerate one bar on one channel" on 5/28/21 and Multi Riffs haven't been mentioned in this thread.
Read through this thread and the one mentioned and you'll see folks don't think BIAB can do this and may be confused by your proposal and gifs that Reaper is doing what BIAB can't do. The plain truth is Utility Tracks generate RealTracks with the same steps that's done on Legacy Tracks. In addition, Utility Tracks can also do partial bar regeneration.
You are highly respected and perhaps if you demonstrate Utility Tracks generating RealTracks, highlighting bars and regenerating only the highlighted regions like you've demonstrated in Reaper, they'll have a better understanding.