Did the Grinch plan this? Oct. 1 was the deadline for stores to switch payment terminals to handle data-chip-embedded cards. But that’s resulted in slower transactions and longer lines just in time for the holidays. Customers are suffering amid a battle between retailers, the finance industry and the FBI over how best to prevent U.S. fraud, which cost $30 billion last year. Retailers are fighting interchange fees of $61 billion, and state attorneys general, adding more good cheer, warn that chips aren’t enough: They’ll soon push to require credit card PINs as well.