You need mouse broadcasting to aim abilities or to "click to move." Even 'force move' if bound to a key and broadcasted by key-map, doesn't work unless mouse broadcasting is on. [Well it works, but the characters go off in a random direction; e.g. you can't direct them.]

That said, it's completely viable to resolve all planned button presses and mouse clicks (including shift clicking) via key-maps. This is useful if you for instance use a no-generator build on a character or have an ability on left click that you don't really want to spam.