The chaos caused by India’s ban on high-denomination rupee notes has provided a boost to a national cashless payment platform that has struggled to gain traction.Central bank data show that the government-backed Unified Payments Interface logged 358,000 transactions in the first nine days of December, shooting past November’s 287,000 total, as some Indians sought to circumvent the cash shortage that followed the government’s surprise graft-busting move on Nov. 8.Prime Minister Narendra Modi’s action to invalidate old 500- and 1,000-rupee notes left India with about a fifth of its currency in circulation and caused a scramble for cash that has seen millions lining up at banks daily to deposit the notes or exchange them for new denominations. That’s pushed more people toward the UPI, which has been slow to take off amid criticism that banks are not promoting the service enough.“For the customer and consumer, it is cheaper and easier to use UPI than most other ways of payments like cards,” Stuart Milne, chief executive officer for HSBC Holdings Plc’s India operations, said in an interview at Bloomberg’s Mumbai office last week. The platform is “beneficial to both customers and merchants,” he said.The Reserve Bank of India’s UPI transactions data for November and December are the earliest available usage figures for a platform that was unveiled in April. Partner banks’ mobile applications only went live officially in August.Launched as part of the country’s bold push to yank its cash-based economy into the 21st century, the UPI allows users to make transactions over their mobile phones including cash transfers to other users, and payments to utilities and some merchants.Anyone with a smartphone, an account at one of the UPI’s partner banks and a mobile number linked to that account can download the platform app. Users are enabled after registering on the app, which usually takes less than five minutes.Still, the UPI has drawn criticism from a number of commentators who say that education for potential users is lacking and the platform’s partner banks aren’t doing enough to promote it.The system has attracted 2 million registered users, according to A.P. Hota, CEO of the National Payments Corp. of India, which is backed by the Reserve Bank of India and manages the UPI.That’s just 8 per cent of the target of the 25 million users that Hota would like to achieve by March, he told BloombergQuint recently.By contrast, digital-payments provider Paytm Mobile Solutions currently has 165 million users and expects to process 2 billion transactions this year, founder Vijay Shekhar Sharma told reporters last week.The cash shortage may prove to be a catalyst for the UPI: A government committee formed to promote digital payments in India in the wake of the chaos is focusing on encouraging more merchants to accept the UPI and take on more point-of-sale devices.With the UPI already in place, boosting acceptance of the payments interface is achievable in weeks, billionaire Nandan Nilekani , the former head of software exporter Infosys Ltd. and a member of the government committee, said following the group’s first meeting last week.“The critical thing for UPI is to get more people signed on,” HSBC’s Milne said. “Once you get a critical mass of people who have a handle, then the thing will grow very quickly.”The system is already replacing debit cards in India and has the potential to one day replace credit cards in the country, Milne said. That has ramifications for HDFC Bank Ltd . and State Bank of India , the nation’s biggest credit-card issuers, according to RBI data.“Banks with a high share of credit cards won’t be so happy,” Milne said.