It's not just a theory that circulates in various circles on the Internet. There is a desire on the part of national governments to eliminate cash, or at least reduce the amount in circulation. Currencies have a characteristic that runs counter to the desires of government: anonymity. We you buy something at a store or from a neighbor and pay in cash, there's no record to trace that transaction unless there is some document completed and filed.
Countries will give all sorts of reasons for abolishing cash, and many make sense, at least on the surface. Cash can be lost or stolen. It can be used to facilitate illegal transactions such as the sale of drugs. It also enables the “underground” economy to function whereby people exchange their labor for cash payments that are never reported, and hence not subject to income tax. People can run businesses on a “cash-only” basis and accomplish the same thing. It is argued that this underground economy unfairly shifts the burden for paying taxes to law-abiding citizens and rewards the so-called tax-cheaters.
Would the US government intervene in another nation's financial affairs to promote the abolition of cash? See page two.