As someone that games on both PS4 and PC, I find the comparison between the two useful and relevant. Not because if I ran the game on PC it would look like the DF screens, because it wouldn't, as my PC is not great. But because I can see what the maximum or high level PC version looks like before I would need to tone it down in settings. If the screens show a vast amount of difference between the two versions, then I know to get it on PS4, as it will likely perform better than my PC. If they are close, it means my choice is greater, as chances are my PC with lower settings will still look pretty good.
This may not make a great deal of sense to most, as you likely all have a better card than me, but it is good for me to know when thinking about what system I will buy a game for. There are other factors, but it certainly helps me decide.