After reading Autocad name, I thought you wanted to propose users to edit vertices in 3D!
If you look further in source code you'll see that walls and rooms are not bound to each other. This makes undo / redo easier to program, and less consistency tests to add. Note also that at the moment, walls are defined by their two end points and not their corners, and that rooms can be used for other things like drawing paths or only a part of real world room. Good luck to introduce common vertices in a kind of model not foreseen for that!