This is a case of you looking at it like an investor, not a gamer. Nothing is added for gamers. You are not getting an extra game for your library; you are merely getting a talking point for your console of choice. This could be comforting for console warriors, but that line of reasoning doesn't hold up from a consumer standpoint. There is no upside for the consumer in this isntance--the majority of the market exists on other platforms, and this only serves to withhold the game from them. Basically, the only people who could conceivably be happy with this outcome are console warriors or Microsoft investors (and hint: their investors are largely ambivalent or downright hostile towards the xbox division).
Technically,
almost every exclusive game (first party or otherwise) is merely a "talking point for your console of choice" by this logic. After all, there often is no technical reason why Numerous Exclusive games on Modern Console A can't exist on Modern Console B. All of those come down to "investor-focused" reasons as well. In regards to Microsoft, Sony, and Nintendo, unless we're talking about Kinect-exclusive, PS Camera/touchpad/PS Move-exclusive games, or Wii Gamepad Screen-exclusive games, there's almost never a technical reason for a game's exclusivity. And even then, people could design those peripherals work to be cross platform if they wanted to actually try to reach all gamers.
"But that would be expensive and make no business sense to do!"
Stop thinking like an investor!
Of course, the typical response to that when talking about things like first party developers or "fully funded 3rd party exclusives" is this: "well, the company gets more money to focus on making the best game possible for one platform, instead of splitting their attention between multiple platforms!" Which is a very valid point. And I'd say, if that's the response, why doesn't that apply to Tomb Raider as well? They can now focus on one platform (well, two, assuming they're working on the last gen version, which isn't known yet), instead of 5 or whatever. So by the logic most people typically use to defend first party development, and those "talking point exclusives", it seems like Tomb Raider would qualify as well. Its not like the PS4/PC version was finished and on store shelves, and suddenly got recalled due to a moneyhat. The game is still in development, and all the supposed "first party" benefits apply to them as well (more focused and streamlined development, increased marketing, etc.)
After all, Uncharted exists on Playstation consoles because Sony is putting up the money to do so, and because Sony wants a "talking point for their console of choice", not because a 3rd person action-adventure game controlled by a dual analog controller is suddenly impossible to do on a PC or an Xbox, and only the power of the PS4 can bring it to life.
Halo exists on Xbox consoles because MS is putting up the money to do so, and because MS wants a "talking point for their console of choice", not because an FPS is suddenly impossible to do on a PC or PS4, and only the power of the Xbox can bring it to life.
Zelda exists on Nintendo consoles because Nintendo puts up the money to do so, and they want a "talking point for their console of choice", not because green elven looking heroes can somehow only be rendered on Nintendo hardware.
The console industry, 3rd party royalties, platform holders, and that whole business model
by definition is "investor-focused". We've just grown up with this model, so we accept it as "natural" and "pro-gamer" even if it's just as arbitrary as anything else.
...that's why I say burn the whole thing down, one console standard future, unite as one, and bring an end to this tribal warfare!