(from Hennns)
My fear is that it will turn into a booting competition. for example Imagine if one player takes his turn once in an hour
That's why this is (in my opinion) predestinated for a real-time-game. As a host you know you have a specific time for a game you want... maybe 30, 60 or 120 minutes.
With that option you can make a match where the game lasts precise the time you have and want.
No unfair opponent could stretch the game with waiting each allowed time every turn or hide cowardly behind a big blockade.
So this would be a quite useful feature...