Back in February, there was a very similar deal, where you could get Delta 3X Miles With Airbnb (EXPIRED).
3x Delta Miles With Airbnb
**Applicable on bookings made from August 10, 2017 to October 31, 2017 for stays completed by October 31, 2018. Terms apply.
If you have some Airbnb reservations to make, might as well book via Delta for the 3x miles.
If you haven’t tried Airbnb yet, you can get $40 toward your first $75 trip via my referral.