When hosting and something comes up that is not great for a guest, it would be nice to be able to tell them, "I'm really sorry about that, we'd like to take $50 off your bill to make up for it." But I don't know of any easy way to do that. So we end up having to mail them a check or trading Paypal info outside the Airbnb system.
It would be nice to have a button for current guests to "give them a special discount". Then just say a flat amount discount we want to offer them. This doesn't happen often, but every once in a while something out of our control happens and we want them to feel better about it fast, and enjoy the rest of their trip.
For example, the cable in the area is out for their first day so they don't have wifi. It might take a day to get the cable company out to fix it, and it's nice to offer them a discount for their trouble.