However, things happen. The good airport apps can tell you stuff like "You just got out at Arrivals C/2. Next flight departs from B42, to your right, four minutes. Estimated delay 25 minutes, but boarding still closes in 11 minutes.
Granted, you can get the same info from signage and info screens, but when you've been on your way for a day, tired out of your mind, your incoming flight was delayed and you may not catch the last leg home, having to spend (yet another) night in a hotel with as much character as a helping of yesterday's mashed potatoes, getting the information you need on a small screen in front of you rather than having to go looking is gold. Pure, brilliant gold.
And I really should only need one, which is where this API comes in - if other airports could fall in line and agree on a common API, maybe we could get an app or two which aggregates data from the airports on your journey and presents it in a tidy way.