One use case I expect to become a reality is the following:
As we see our economies drift into deflation more and more products will be produced on demand to minimize inventory.
So customers will be required to pre-order stuff instead of taking stuff of the shelf.

Now producer in order to minimize supply risk can pre-arrange a smart-contract that will split funds from his input directly  to the supplier at a determined price. Likewise the supplier has contracts with his suppliers etc.
So the moment a customer pays up a contract funds flow across this network of suppliers and production is triggered with minimum overhead. A contract may also choose from various suppliers based on price, production time, location etc so as to minimize price or delivery time based on end-user preference.