If you're a used car dealership you can:

* Avoid paying any shipping costs, and require the car be driven to you in person

* Have a shop attached to the dealership for inspection to avoid paying a third party

* Have a person at the ground level look over the car and refuse to accept ones that are obviously junk, minimizing wasted time and money

If Amazon is literally just acting as a front-end/advertisement for Ford and has 0 involvement than most of this doesn't apply.

It's only a concern for places that act as a true online retailer, taking on all the inventory and risk associated with it.