Good explanation Paul!
Well when we added the landscape phone, I was thinking to change the icon phone in the property panels to landscape phone and the ALL icon to phone but ... as you explained it indeed the lowest is actually the ALL icon ... so it will create only confusion.
And also in the icons in the bootstrap property panels are for the devices and UP.
That is why we had this discussion:
So I'm still not convinced about the best icons in the bootstrap properties panel and how should they switch.
As indeed sometimes you want quickly to switch to another one for just settings without changed the view.