4K is going to really not matter much for a while simply because the average computer doesn't have good enough graphics to make good use of it. The resolution jump is huge and so you need a lot more GPU memory and processing power to do the same things at a higher resolution. Games are now really taking good advantage of 1080p, so we are another 5-10 years away from 4k being a real thing in terms of mainstream gaming…
The real elephant in the room is the poor scaling of applications, on my 4k laptop screen on windows 8.1 I tried making it work for a few weeks using windows' scaling settings, but caved and just set it to 1/4 resolution and haven't looked back. On a small screen the benefit of more pixels just doesn't outweigh the downside of many apps being unusable.