One connection I haven’t seen people make yet is that Amex Platinum (one of the most high end “perks” cards) announced a partnership with AirBnB at pretty much the same time. In fact they changed some of their benefits structures to focus on AirBnB credits, replacing/augmenting existing hotel credits.

I would not doubt that they had a hand in this change as they did not want their users mad at the experience they would get going through AirBnB.