Basically it solves NP-complete problems that are solvable because of small set size and some clever constant optimizations. There are industries where it's a useful thing for scheduling, for example. Or you may want to solve travelling salesman when planning a trip.
Some real-world examples with a little more flavour:
* designing utility networks (e.g. energy / telecommunications) to be cheap / robust
* routing vehicles / ships / parcels to serve all customers cheaply
* dispatching and arranging emergency services vehicles (e.g. ambulances) to best cover anticipated future demand
* managing inventory levels in blood banks. it goes off after a while! there are different types, some are substitutable. which types are better to keep in stock?
* figuring out the most profitable way to chop animals into different cuts of meat
