The idea of a "digital dollar" will once again rear its head before the U.S. Congress on Tuesday.

The U.S. Senate Committee on Banking, Housing and Urban Affairs will hold a hearing on "The Digitization of Money and Payments." While few details have been released, the witnesses – former Commodity Futures Trading Commission (CFTC) Chair J. Christopher Giancarlo, Paxos co-founder and CEO Charles Cascarilla and Duke University Visiting Professor of Law Nakita Cuttino – suggest the focus may center in part around central bank digital currencies and stablecoins.

The hearing may tread similar ground to a recent one hosted by a subcommittee of the House Financial Services Committee, which addressed questions of financial inclusion and how best to send relief funds to U.S. residents quickly and efficiently. Witnesses at the time called for tried-and-proven alternatives to building a novel tokenized system.

Cuttino, in prepared opening remarks, said while some U.S. residents might turn to digital banking and payment systems, "low-income Americans disproportionately prefer to transact with bank tellers."

Digital systems come with their own drawbacks: nearly one in five Americans don't have smartphones, limiting their access to digital banking services, while nearly 10 percent don't have alternative internet access in their homes. Cuttino also raised questions about the business models for central bank digital currencies and stablecoins.

"If services are 'free,' what alternative trade-offs are consumers making (e.g., consumer data)? Is consumer data being used to exploit behavioral weaknesses to their detriment? Additionally, are consumer conditions improved by a shift to the novel solution? Ultimately, fintech solutions should not merely move the most Americans from the fringe financial marketplace to a fringe digital economy," Cuttino says.

Read more: How the COVID-19 Crisis Revived the Digital Dollar Debate

Cascarilla addresses concerns around the accessibility of financial services in his opening testimony, noting that banks today have limited hours and accessibility.

"Consumers and institutions alike are held back by the inability to have timely access to their own funds because of settlement delays in bank transfers, international wires and other activities that can take over five days to settle," he says. "This makes it difficult to manage other payments with any kind of predictability. On an economy-wide scale, this creates a complex daisy chain of loan obligations and unnecessary intermediaries."

This architecture must be updated for the 21st century, he says, echoing a common refrain from former CFTC Chair Giancarlo, who has similarly advocated for future-proofing the dollar.

For his part, Giancarlo – appearing in his capacity as a director of the Digital Dollar Project – will explain and advocate for a tokenized version of the greenback.

"The Digital Dollar Project believes the opportunity is at hand not just to imagine such an ecosystem, but to actually build it with such services for low-income and underbanked communities as priorities from the start," he says in his prepared testimony.