The Bankrate survey was conducted by Princeton Survey Research Associates International over the telephone in July with 1,002 adults living in the continental U.S. The LendEDU poll was conducted online by OnePoll and surveyed 1,000 American consumers ages 18 and up in late August.
On the digital currency side, a leader at major cryptocurrency investing and trading company Coinbase said investors should still be cautious.
"Everyone should have a bit of exposure to digital currencies because [it] looks like [the] future," said Adam White, head of Coinbase's GDAX exchange. But there's "still a very real chance" some of the digital currencies fall "all the way to zero."
White also said digital currency investors should still heed two investment adages: Never invest in what you don't understand, and never invest more than you can afford to lose.
The cautionary tone echoes what some market watchers have been saying. Elliott Prechter, who writes about the Elliott Wave Theory widely followed by traders, said in July that bitcoin appears to be nearing the fifth and final wave of its latest run higher.
Bitcoin has more than quadrupled in value this year and was trading near $4,718 Monday, according to CoinDesk. Another digital currency, ethereum, has soared more than 3,000 percent to around $300.
The entire universe of cryptocurrencies has multiplied eight times in value this year to $150 billion, according to CoinMarketCap. That's still a tiny fraction of the roughly $200 trillion in gold, cash, stocks and bonds.
Nonetheless, digital currencies and the blockchain technology underlying them have increasingly become part of the discussion on Wall Street this year.
Fundstrat's Tom Lee predicts bitcoin will multiply five times more to $25,000 by 2022. He also laid out in a note on Friday how even a 2 percent allocation to digital currencies would have added about 2.29 percent to total return for a traditional portfolio with 60 percent allocation to stocks and 40 percent to bonds.
Paul Brodsky, founder of Macro Allocation, discussed cryptocurrencies in the Sept. 19 issue of his newsletter. In a phone interview with CNBC last month, Brodsky said the development of digital currencies may be enough reason for stock investors to be cautious on the growth potential of the market's high-flying technology stocks.
"We may have identified something that is the next generation that will take market share from Amazon, Facebook and Google," Brodsky said. "We'll be becoming more passive on how we allocate wealth into the markets at a time when we can maybe identify a next generation of wealth creators."
Blockchain developers, particularly those behind ethereum, believe they are creating a new, decentralized kind of internet.
But for now, the young investors on Robinhood's platform like technology stocks — Apple, AMD and FitBit were the three top-traded stocks on the app in September.
The company that built its business on cutting stock trading commissions also doesn't see crypto in its immediate future, Tenev told CNBC last week. Instead, he said Robinhood's plan is to expand its stock trading business and, in five years, offer the same kinds of banking products offered by JPMorgan Chase or Bank of America.