They were created at a different point of time for the site, when there was more of a fly by the seat of your pants instead of having some sort of direction. Since the reason for why there are not additional categories for digital PC platforms is also applying to Steam or GOG. We do not have the correct solution in place, so those categories still exist. Whenever we get to the point where we can assign tags to items, those categories will technically go away and there will be only 1 category: PC Digital Download, and a user can apply filters to that category to show items that were released on Steam, Gog, Epic, or any of the 50 other digital platforms.