“Rite Aid and CVS have been accepting contactless payments for quite a long time,” Mr. McLaughlin added. “We look forward to them turning the functionality back on in their stores.”

Apple has not released data on how popular its new product is. But on Apple Pay’s first day, at Chase banking services seven times more people added Chase credit cards to Apple Pay than signed up for new credit cards, Avin Arumugam, Chase’s digital executive director, said in an interview with Bloomberg.

A great deal is at stake. MCX’s payments system helps merchants keep track of customer shopping habits across the dozens of merchants who plan to accept the payment product. That is a potential treasure trove of data for retailers, who wish to better target consumers with deals and loyalty programs.

This also gives retailers the potential ability to cut credit card companies out of the payments process entirely. MCX’s system, CurrentC, will be linked to a consumer’s debit account, according to the company’s description of the product. By bypassing credit card companies, MCX merchants could potentially save money on the fees they pay per transaction.

MCX retailers include large chains like Best Buy, Gap Inc. and Walmart. Over all, they represent more than $1 trillion in annual sales, 110,000 total stores and more than one-fifth of total United States retail sales volume, according to the coalition.

Technology companies like Google and PayPal, as well as mobile carriers like Verizon and AT&T, have all tried — and failed — to persuade consumers to pay for things with their smartphones.

But many believe that if any company can gain consumer adoption quickly, it’s Apple.

“Apple actually has a really good shot at being successful here because they’ve solved a lot of fundamental issues that others haven’t in the past,” Mr. Moorhead said. “In particular, the user experience issue. It’s simple, easy and secure to use.”