Wel, yes and no. From the perspective of a (mainly) PC gamer:
- The Xbox One S/X is a good UHD/4K Blu-ray player.
- There are still some games exclusive to the Xbox One platform not available on PC, for example: Halo 5: Guardians, Sunset Overdrive and Forza Motorsport 5.
- On top of that, you have back compat, which adds more games that are not available on PC to the mix (Gears of War 2, Halo: Reach, Red Dead Redemption, etc.)
Finally, this upgrade it's not only "the same games at 4K", several "X enhanced games" have already been tested and the improvements go beyond resolution; we're talking more texture detail and higher/more stable framerates.
I intend to buy an Xbox One X for those elusive exclusive Xbox games (I already have a PS4 Pro and a GTX 1080 Ti equipped PC with a ton of Steam games) and to play some 4K Blu-rays for sure. Anyway, if you don't care too much about graphics quality the Xbox One S is a FAR better value of course.