Consumer use of mobile finance, banking and insurance apps jumped 71 percent in 2019. In 2020, however, they’ve gone from nice-to-have to essential.

Use of contactless mobile payments — services that once struggled to catch on in the U.S. — is surging as people come to see their phones as the safer way to pay.

Tech firms see the opportunity they’ve been waiting for as shoppers and business recoil from paper money. Who’s hurt when legal tender goes away?