Several government agencies have made deeper moves into crypto oversight, leaving a trail of angry executives and unresolved political questions. And there's still no sign of a central bank digital currency, leaving the U.S. at risk of falling behind other countries in the race to support faster payment processing.

The digital currency and related distributed-ledger technologies could "enhance the efficiency, effectiveness and stability of the provision of payments," according to an interpretive letter issued by the Office of the Comptroller of the Currency.

Silvergate and Avanti are among the banks pioneering the incorporation of smart contracts, cryptocurrencies and other cutting-edge instruments into mainstream financial services.

The Securities and Exchange Commission last week accused Ripple of breaking securities laws, raising questions about the future of banks' ties with the company.

It's important to consider difference uses and types of blockchains based on need and project management strategy for financial and payment technology, says Worldline's Hubert Marteau.

The company did not disclose the nature of the suit, but CEO Brad Garlinghouse has long disputed the Securities and Exchange Commission's claim that XRP is a security, not a currency.

They're among a handful of companies willing to hold clients' digital assets for safekeeping. Many of their peers balk at the reputational and financial risks.