My understanding of that reference is that the physical disc itself is only compatible in the XB1 drive - you won't be able to use the same game disc in your PC drive. Presumably if you buy XB1 physical you'll need to download to PC, and vice versa. (Assuming there even is a physical disc in the PC box and not just a download code anyway.)
As DGH suggests, the PlayAnywhere feature implies - at least to me it does - that you should be able to play on either XB1 or PC regardless of whether you buy physical or digital, with the understanding that you'll still need to install files specific to the platform on each.Xbox One game disc for use only with Xbox One systems.




