The main difference between them is latency and stability with multi-channel audio. You get dropouts, loss of sync, much higher latency (if you use it for any sort of production with DAW/VST).
For eg. I can run 16x channels audio with 2ms...
It'll need DP2.1 to be a thing first. DP1.4 doesn't have the bandwidth. Look at the issues XR4 is having due to DP1.4 requiring everything to run OpenXR and DFR otherwise you're playing at a Quest 3 resolution.