Rolled out in October, Apple Pay is a mobile payment and digital wallet service from Apple Inc. that allows users to make payments using iPhone 6, iPhone 6 Plus, Apple Watch-compatible devices including iPhone 5 and later models as well as iPad Air 2 and iPad Mini 3.

Apple Pay preserves the existing card network payments system while CurrentC does otherwise.

"The premise behind MCX is avoiding interchange," Ron Shevlin, a senior analyst at the research firm Aite Group in Boston, said.

Indeed, there are no indications CurrentC will include traditional Visa and MasterCard credit cards when it launches in 2015, according to some experts. That may not represent a significant issue to credit unions.

"In the scheme of things, interchange is not a big factor in the income of most credit unions," Shevlin said.

Some industry watchers experts also believe that regardless of MCX, the interchange trajectory is downward.

"Interchange is going away, period," Tim Hayden, co-author of The Mobile Commerce Revolution, predicted.

There have been conflicting signals on the future of interchange coming from MCX.

"[MCX]…will have open loop credit cards as part of our program when we launch," Davidson said at Money20/20.

However, he did not elaborate on whether MasterCard, Visa, American Express and Discover will be in CurrentC.

"[Seventy-five percent] of transactions that occur at the 80 plus merchant brands [in MCX] are done where consumers use their own money," Davidson said. "Cash, check, debit card, gift card, prepaid card. We have a solution for 75% of those transactions on day one."

As for what that solution will be, some experts have said CurrentC's preferred payment rail will be ACH for linking to a consumer's checking account to extract cash. This method will likely end interchange and Visa and MasterCard credit and debit fees.

Mary Monahan, a payments expert at research firm Javelin Strategy + Research in Pleasanton, Calif., said MCX wants more control of the sales process.

"Many consumers want to use credit cards and it takes decades to change behavior," she explained. "Also, the MCX merchants want to make sales."

Monahan believed MCX will have to loosen up on open loop cards or the merchants will risk losing sales.

CurrentC is not just about interchange. At Money20/20, Davidson talked about how the MCX merchants wanted to use transaction data to get closer to their customers and to serve them appropriate rewards and offers. He said because CurrentC will deliver a better shopping experience to consumers, they will use it.

There will also be ways to build CurrentC payments into a financial institution's mobile banking app, Davidson told Money20/20 conference attendees.

Read more: Shouls credit unions play along with CurrentC?

Opinions are divided on whether credit unions should prepare to play along.

At the $900 million Financial Partners Credit Union in Downey, Calif., Lori Reeves, SVP, said, "We don't want to be left out of any option."

David Hall, SVP at the St. Petersburg, Fla.- based payments CUSO PSCU, offered another take.

"The disruption with Durbin has created an atmosphere where many financial institutions are not attracted to the MCX model," he said.

The bitterness over declining interchange will repel at least some credit unions in Hall's view.

Michele Orndorff, a senior manager with consulting firm Kurt Salmon in New York, echoed that reluctance.

"I don't see FIs embracing MCX," she predicted. "There is a wide bridge between financial institutions and MCX right now. There's too much bad blood."

Shevlin said, "A lot of bankers are looking at MCX as though it is radioactive. They don't want to get near it."

Financial institutions might not be willing to cooperate with CurrentC at the outset, according to Tommy Marshall, a partner in the banking group with global business and technology consulting firm Capco.

"My bet is that they won't share interchange with merchants. I can't imagine a bank giving CurrentC a cut of interchange."

Still, some are optimistic about the future.

"I do believe credit unions can win with CurrentC," Hayden said. "They should be linking to it in their mobile banking apps."

At least some consumers will respond very positively to CurrentC and a smart credit union can deepen its ties to them by linking up with the merchant consortium, he added.

"A credit union should work to make it simple to pay with CurrentC through a credit union account," Hayden said.

Who's right and who's wrong? That may be still too early to call. The other question is does CurrentC have a chance of success. The bulk of its merchant owners make it impossible to ignore but, in a way, that may also be a flaw.

"It is difficult to manage consortiums," Gil Mermelstein, a managing director with consulting firm West Monroe Partners LLC in New York, said.

Many MCX members are mortal enemies, according to some experts. Walmart and Target fight over every sale and Best Buy competes against both retailers. Likewise, Kohl's spars with Kmart, Sears and other retailers. While they may all be united in their hatred of interchange, will that overcome their mutual antipathy? Some experts are skeptical.

Shevlin is doubtful the MCX business model is sustainable. By his math, wiping out interchange may end up saving the retailers 1% or 2% in gross sales. That's a huge number for this group.

"For MCX to get consumers to change behavior will require coupons and deals that will cost more than the interchange savings," Shevlin said.

Apple Pay has singlehandedly established that there is consumer demand for mobile payments at the point of sale. It is likely that there will be a rush of would-be competitors with CurrentC among them. The question remains on who will be left standing.

"The best bet for financial institutions is to look forward and think about the broader mobile landscape and where they will play in mobile payments," Orndorff said. "Mobile payments are coming and you need to be there."