Sure, having two inputs does require some ui to switch inputs. That said, you could get the same user experience by simply only plugging one device in to a monitor even if it has multiple inputs.

If it was possible to use adapters, this problem would be much reduced, but as it is, it's pretty much impossible to plug in a desktop or game console in to the Apple monitors. And at least for me, having a joystick on the back of the screen for input switching is less problematic than a monitor which only works on some of my devices.