He adds: "Because it is store credit system it may well not attract the concern of any regulators" - but again, herein lies the rub: regulation.
Regulation and central banks
Although store credit itself might sit outside of the purview of the FCA, PRA and the Bank of England, as one is introducing a competitive medium of exchange, there would have to be some oversight.
Turnbull recommends the government/FCA setting up a currency sandbox to test ideas. "It is essential", he says.
Pirrie agrees that a sandbox is a great idea for testing the idea.
He says: "Regulators need to strike the right balance with their regulation. Perhaps a regulatory sandbox that could oversee experimentation, adaptive frameworks and, of course, full transparency.
"Like any phenomenon, usually there are risks. Where there are risk, the general public will need protecting and that means regulation and rules start to appear."
Perhaps unsurprisingly, the former chief executive of the Bank of England advocates the function and form of central banks as the best possible solution for regulation and trust.
Haldane says: "When it comes to issuing ultimate means of settlement, the ultimate means of payment, of course there are alternatives to central bank money.
"We have had them in the past before central banks and central bank money - trading beads or gold or furs or yap stones - but these were found to be fairly ineffective means of exchanging claims."
Haldane adds: "It depends what it is that you want an alternative to do. You think of the functions of central banks. One of these is to keep the financial system safe and sound - and the financial system has shown itself not able to do that of its own volition."
The great financial crisis, he says, shows that allowing the system to govern itself was a "ridiculous proposition". Regulation, he says, is a "dirty business but someone has to do it. It does not have to be a central bank - in some places it is not - but someone has to regulate the financial system".
In other words, central banks facilitate the basics of economics.
Pirrie agrees that regulation is key, and that regulation and trust comes largely from the existing system of central bank governance.
He explains: "They offer a payment mechanism that supports global trade and that is backed by a huge industry - that would be very hard to replace overnight, or even over a decade. Do we need central banks? Currently yes.
"Is there an alternative? Probably. However, we have to consider time, politics and regulation which could prevent an alternative from ever meaningfully emerging."