The key point with the Door-to-Door option is that the seller themselves is guaranteeing a delivery date – they are saying when they will get the order to the buyer’s door.
The Door-to-Door option is recommended for sellers with warehouses in multiple locations. eBay can’t automatically calculate the delivery date in this case, so instead sellers upload rate tables that define shipping speed and cost by region.
From 2019, sellers using this option will have to compensate buyers for late delivery, even if they meet their handling time. That makes sense, because the seller is guaranteeing the whole delivery “door-to-door”, not just the handling time.