How many devices output 2.1 though? Those of us with older hardware would prefer DP support for our aging hardware.
Sure I guess. I'm not saying it isn't nice to have, I'm just saying it's not really missed that badly. You could always use Club3D's DP 1.4 -> HDMI 2.1 adapter which supports DSC to get 4k120Hz 444 on the CX using a non HDMI 2.1 device.