Forget dish sets and kitchen appliances, some couples are putting bitcoin on their wedding registries.

Some tech-savvy wedding-goers are gifting the digital currency to new couples, as its value surges to new highs. Like purchasing a stock or bond, buying bitcoin is — all going well — an investment in the future. Sounds crazy, right? Bitcoin is notoriously volatile. But if you got married in 2011 your $100 Bitcoin gift would be worth more than $238,000 today.

Business Insider editor Emily Cohn tweeted that the currency was given to her and her husband at their wedding and ultimately proved to be “the best gift we got.” Her husband Ben Eisen, a former MarketWatch reporter, wrote about the experience in The Wall Street Journal in 2016, noting that one bitcoin had been worth $230 around their wedding in September and had jumped to $430 by the end of the year. As of June 26, less than a year later, it is worth $2,383.

The unpredictable nature of the currency that paid off so well for this couple also means the gift may not be the best choice for the average wedding couple, said Neeraj Agrawal, a spokesman for bitcoin advocacy group Coin Center. “Because it is so volatile and has a learning curve, use your best judgment on whether or not the happy couple would genuinely appreciate a cryptocurrency gift,” he said.

While people are giving bitcoin, there hasn’t been a tipping point. Honeyfund, a honeymoon registry that allows guests to give cash rather than gifts, has seen more than a dozen customers donate in bitcoin, said chief executive officer and co-founder Sara Margulis. In recent years, more than a dozen customers have chosen to route donations to the site from bitcoin wallets. Zola, a wedding registry website, has had just two cash funds created for bitcoins since 2013, a spokeswoman said.

If you do decide to gift in bitcoin, the same etiquette would apply to the currency that applies to cash gifts, Agrawal said, spending an appropriate amount of money and accompanying it with a card. People should spend anywhere from $50 to $250 on a wedding gift depending on their relationship to the bride and groom, said etiquette expert Jacqueline Whitmore. That’s 0.02141 to 0.10719 in bitcoin at its current value. Friends of marrying couples give an average of $99, according to a study from American Express, and family members gift an average of $127.

Others wedding industry experts say bitcoin is about as common as gold coins from a pirate ship. That is, they’ve never been asked to add it to their wedding gift registries. A spokeswoman for MyRegistry.com said there’s no evidence any of the 153 million gifts added to their system since it began in 2005 were for Bitcoin.

“I would expect it to pop more as millennials come into the wedding age,” Honeyfund’s Margulis said. “It’s something you will do if your friends and family are already into bitcoin — not something most couples would do.”

That’s another rule when gifting Bitcoin: Make sure to gift it only to people who are ready to dive into cryptocurrencies, Agrawal said. Though Eisen and Cohn are thrilled with their wedding gift and how much its grown, others may end up forgetting about the digital present and leave it wrapped up online. Avoid using a wedding gift “as an opportunity to proselytize a technology you personally believe in, but the recipient could not care less about,” Agrawal said.