The technology that allows customers to tap their smartphone to pay rather than using cash or cards is taking a while to get off the ground. There are two problems to overcome: hardware and customer awareness. In terms of hardware, it depends on retailers being willing to upgrade their point-of-sale terminals. Customer awareness include instilling the confidence that paying in this way is as secure – if not more secure – than using a credit card.

The UK is ahead of the US in terms of the percentage of terminals that can already accept mobile payments, although in the US in the last nine months the number has grown from 120,000 to 400,000. The London Olympics is being seen as an international showcase for mobile payments, and Visa (one of the bigger companies promoting the idea of mobile payments) has provided 140,000 terminals in London, including 5,000 taxis and 3,000 point-of-sale venues at the Olympics.

Source: https://news.cnet.com/8301-1035_3-57478991-94/visa-mobile-payments-will-hit-mainstream-in-2-to-3-years/

iphone with attached earphone and Visa card beside