"Two Eorzea days" and "Two minutes" are the same thing, "Only shows up at night" and "Only shows between :30 and :59" are the same thing.
Developers won't be hindered by a real-time day/night cycle if they want to implement a game mechanic that is limited by time, really. All it'll do in the end is prevent a particular subset of people from experience the shift from day to night, how much this affects the game is yet to be seen but that is all there would be to it.
