I consider the view that #blockchain has no uses cases at all only a little less ignorant than the one that it solves everything.

What about car contracts, that shouldn't be paid by more then one person?

A decentralized car and/or mileage registry is an excellent use case, as is any registry that needs immmutability and double-spend prevention. Privacy issues usually make things more complex than they seem at first, though

How is decentralization a benefit here?