“Add Booking Holdings Inc. to the list of e-commerce companies betting that a tighter control over the payments process will create a better experience for consumers—and a new revenue stream. The online-travel company announced earlier this month that it was launching a financial technology unit that would aim to simplify some of the monetary hurdles of international travel, from booking a room at a hotel where there’s a different local currency to making a purchase commitment for a trip that won’t take place for a few months.”