[patio11]

Some people have yen but want to buy things, like a tanker full of oil, priced in dollars. There once existed a specialized profession of very expensive middlemen who would facilitate this transaction. The transactional costs would have paid for a nice house. Computers can do it for a tenth the price, saving money for folks in the non-finance economy when they're doing things that the non-finance economy very urgently wants them to do.