This is not about making it easier to get deliveries. When an Amazon delivery doesn't work out, they refund you. This is about reducing Amazon's costs. Don't do it. As long as we all don't do it, Amazon will credit us when deliveries fail.
Delivery has turned into minimizing every excess second. I wager within a few months most of these amazon keys will be ignored as they leave packages on the driveway. I wouldn't buy this unless it comes with a guarantee it will be used.