Actually I've added it because I generally enjoy the idea of giving a place for alternative. And both booking with all this humanness triggers and Airbnb with this option of auto-confirm booking...
Did you ever got the foreign country and get the ‘sorry we're overbooked’ or just simple and scary silence after being charged by AirBnb for booking?
I faced this problem three times in a row at Canary Islands last year. Sure, airbnb returned the money and even give some over to compensate but sleeping in the airport isn't a brilliant way to start exploring Spain, right?
And now project closed like 1/4 of presale without this annoying ads and whistling from every square about it.