Why 24fps is not enough for HDR movies

[disputes123]

I don't understand these things very well, I hope you can shed some light on this.

I bought a BenQ GL2460 monitor (has D-sub and DVI-D as input connectors) which came with a D-sub cable. I'm sure the quality using DVI is much better so I want to buy one, but there are a lot of different options in the DVI category as I'm wandering through eBay. Here is a photo of my PC input and Here of screen input.

I am grateful for any help.