Wasn't the problem that 5K displays(or maybe it's just this specific one?) are notoriously difficult to make it work on windows? Last time I looked into getting one I found out that it just wouldn't work without getting a thunderbolt card for my AMD based system, or a DP 1.4 compatible gpu.

On the other hand, HDMI 2.1 can now support 8K@60hz, so maybe this is not an issue anymore.