Hi.
The Witcher 3 is D.R.M. free.
Here is a short description on what D.R.M. is.
https://www.eff.org/issues/drm That being said, the updates can be downloaded only when you go online on your personal XBOX account, where you reedemed the game code.
XBOX architecture (GPU, CPU, mainboard) is standard, so it is more probable that in case you stumble upon a bug, there are more people experiencing it as well. The only thing you can do on a console, if you have unbearable issues, is request a refund from the retail store.
It seems strange that you expected a PC code in box, since PC games and cosnole games sold in retail stores clealry state what platform they are for.
I suggest buying the PC version instead, on the next GOG.com sales, if you want to support CDProjekt RED directly.