[tjoff]

Well, 4K is not exactly a requirement. And while most older don't have the ability to swithc USB my U2415 displays (released in 2014) supports switching input over DDC. And honestly, I'd expect any half-decent display sold in the last decade to support it as well. But I could be very wrong. The samsung and AOC display I have connected at work also supports them and the samsung is quite old. For USB though I have to press a button. Or use the excellent virtualhere software for connecting USB over the network (that I could easily script to switch over usb as well).

I have a short script that will allow me to change input on a specific display. Very handy. However please note, that while this does work for HDMI, DVI and Displayport only DVI/HDMI seems to have an active connection when another input has been selected.

That means that while I can switch to another input I can not switch back from the same computer but must install something on the other machine to give it back. This is of course exactly what the linked article is doing, but with HDMI/DVI I don't have to have that requirement. And on top of that, operating systems in general seem to believe that, when using displayport, switching to another input is equivalent to disconnecting the display altogether and thus remove it and rearrange windows etc. Insanely frustrating.

Again, no problem with HDMI/DVI. So although Displayport is a much better interface and I've been a strong advocate for it, these issues makes me hate it with passion.

DDC can also be used to change display brightness, which in my opinion is way too cumbersome to do manually (especially if you have more than one display).