He intends to hold the bitcoins, rather than convert them to dollars. As an investor in the art market, where bitcoin is also increasingly present, he sees an opportunity to make even more money. Bitcoin has also been appreciating at lightning speed lately.

"I think the demographic of the crypto user is a younger millennial, but, that being said, you have a lot of people come over from other countries, who are buyers from different places, who like to trade in different types of currency. Not everyone wants to trade in dollars or yen or euros," Shaoul said.

Shaoul is redeveloping a building on Manhattan's Lower East Side, turning it into condominiums priced between $700,000 and $1.5 million. He admits that there is currently a lot of inventory in the market, and therefore having an edge over his competitors is especially key. Bitcoin, he hopes, will be that edge.

"Our buyer has evolved, they've moved from mom and pops to young people who want to pay with various forms of payment," said Ben Shaoul, president of Magnum Real Estate Group. "Cryptocurrency is something that has been asked of us — 'Can you take cryptocurrency? Can we pay that way?' — and of course when somebody wants to pay you with a different form of payment, you're going to try to work with them and give them what they want, especially in a very busy real estate market."

Bitcoin is already in retail and restaurants — so it was only a matter of time before the cryptocurrency took on real estate. That time is now. Bitcoin is slowly making its way into closings on everything from Lake Tahoe land in California to Manhattan condos to single-family homes in the heart of Texas.

Others, however, are not as comfortable with the relatively new currency. The first ever single-family home sale in Texas involving bitcoin was announced last month. The buyer, who works in the tech industry, purchased the newly built home in Austin using bitcoin, but the seller, a custom homebuilder, wanted the currency converted to dollars during the transaction.

"Austin is a really technologically advanced city, I'd say, so I was surprised we hadn't heard anybody wanting to do this before," said J Kuper at Sotheby's International Realty, which brokered the deal. "But, candidly, we didn't know how to do it. It was a quick challenge and scramble to figure out all the moving parts, but we were instantly excited about the opportunity to figure that out."

They used BitPay, a global bitcoin payment service provider headquartered in Atlanta. It converted the bitcoins into dollars for the buyer. Given that bitcoin's value is a moving target day to day, the risk was all on the buyer side. The seller agreed to a fixed price in dollars.

"We found that on the day of the closing, we were kind of watching it [bitcoin's value] through the day," said Kuper. "The timing actually ended up perfect for the exchange, very well for our client, so there was really no hesitation, no need to postpone."

Kuper said the client got a "very fair" exchange rate, though he could imagine how it could've been more volatile. He says bitcoin has proven to be a bit more stable in the past six months.

There is, however, still a lot of nervousness for newcomers to the currency. Neither the buyer nor the seller in the Austin deal would talk about the transaction. Much of the concern may be around the lack of regulation so far in cryptocurrency and the lack of understanding as to how gains in bitcoin are taxed. The Internal Revenue Service issued some guidance on bitcoin and cryptocurrencies in 2014.

"What they said in that guidance is if you hold bitcoin or ethereum or one of these other convertible digital currencies as a capital asset, when you use that bitcoin to purchase goods or services — so for example, if I were to take $1 million in bitcoin to buy an apartment building or something — to the extent that bitcoin has appreciated since I acquired it, any of that gain, that built-in gain, would be taxed when I used the bitcoin to buy the building," said Jeremy Naylor, a tax attorney and partner at the firm Cooley.

He added that whether people are voluntarily paying that tax might be a separate question, but from a technical, legal perspective, it would be similar to selling stock to generate the cash to buy an apartment. In a direct transaction, buyers simply skip the part where they convert the bitcoin into dollars. Using BitPay, the buyers are 'selling' the bitcoin, and therefore any appreciation is taxable.

The complicated nature of real estate may be why bitcoin has been slow to move into the market. One of the first deals in the U.S. involved a $1.6 million sale of land — a home site — in Lake Tahoe in 2014. Martis Camp Realty President Brian Hull, who brokered that deal, said his firm has not received any other inquiries from buyers interested in using bitcoin.

International buyers seem more comfortable with the currency. Last month British entrepreneurs Michelle Mone and Doug Barrowman launched a bitcoin-priced real estate development in Dubai.

The U.S. market has been slower to buy into bitcoin for real estate. All of the deals so far have been done without a mortgage, and Shaoul said the bulk of those inquiring about his Manhattan condos are foreign buyers.

"This industry of real estate is notorious for lagging behind in technology, and innovation," he said. "Now we are starting to innovate, so we're very far behind. Bitcoin and payments with bitcoin have been around for years. Why it hasn't touched down in real estate in the sale of an apartment is odd, quite frankly."

— CNBC producer Emily Gaffney contributed to this report.