Cryptocurrencies are the talk of the town, and the crypto market has become a playground for speculation. Participants are hoping that the disruptive potential of these new currencies will make them rich. But while it may be tempting to try your luck trading digital assets, it's important to recognize their high-risk nature. With no inherent value but lots of hype, they're prone to volatility.

It might be a sounder financial decision to invest in a business that can benefit from cryptocurrencies' success -- but which was thriving before it got involved with cryptos. If you're looking to put some money to work in crypto, I recommend considering two fast-growing businesses that recently crushed their earnings estimates: PayPal Holdings (NASDAQ:PYPL) and Square (NYSE:SQ). 

A person looking at stock chart on a smartphone.

Image source: Getty Images.

Remarkable first-quarter numbers 

PayPal's first-quarter revenue reached $6.03 billion, while its adjusted earnings per share (EPS) came in at $1.22, easily beating consensus forecasts. Both numbers registered impressive gains over the prior-year period, but what really stood out was payment volume of $285 billion, a record for the company. 

Aided by a pandemic-fueled acceleration of e-commerce, the company added 14.5 million net new active accounts in Q1, bringing its total to 392 million. Management expects to add 52 million to 55 million net new accounts in 2021 and has raised guidance for full-year revenue, payment volume, and earnings. 

Square had a fantastic quarter as well, handily exceeding Wall Street estimates with sales of $5.06 billion and adjusted EPS of $0.41. The company's Cash App was the real star, growing gross profit 171% versus the same period the year before. The popular mobile payments and banking tool produced more gross profit than Square's Seller business, which is noteworthy given that the entire company was founded on supporting small businesses. 

Speaking of the Seller ecosystem, during Q1, Square's mid-market business customers (those generating greater than $500,000 in annual gross payment volume, or GPV) grew GPV at more than twice the rate of the overall Seller group. Having higher transaction dollars coming from these larger merchants provides some economic safety for Square. 

While Square didn't provide specific guidance, the business saw strong engagement with its Cash App in April. Additionally, the Seller ecosystem benefited in the month from continued reopenings. 

Crypto as a growth driver 

PayPal allows consumers, through its namesake app and Venmo, to buy and sell Bitcoin, Ethereum, Litecoin, and Bitcoin Cash. And starting in March, the company added a feature allowing U.S. customers to check out with their cryptocurrency balances at millions of online merchants using the PayPal wallet. 

Although Square's Cash App lets its users buy and sell Bitcoin, the company has more direct exposure to the largest cryptocurrency. It has $472 million of Bitcoin on its balance sheet as of March 31. 

Both PayPal CEO Dan Schulman and Square CEO Jack Dorsey view cryptocurrencies as a major growth engine for their respective businesses. And the expanding capabilities of their consumer apps, Venmo and Cash app, attract more users onto their platforms. 

Schulman said on a recent earnings call, "Half of [our] crypto users open their app every single day." Dorsey, on the other hand, says Bitcoin has the potential to be the internet's native currency. "This is going to be a long-term focus, on enabling Bitcoin to be net currency," he said on his company's earnings call. 

The safer option 

Both PayPal and Square are extremely bullish on the potential for cryptocurrencies, but that doesn't mean that it's the best or safest investment for you. So much still needs to be proven, and right now there's a lot of hype and excitement. A better approach is to consider owning shares in these two companies, which had already built successful businesses before the crypto craze, but which also stand to gain with digital assets' widening adoption. 

PayPal's expanding account base of merchants and consumers results in powerful network effects. The same thing applies to Square's ecosystem of Sellers and Cash App users. This strong competitive advantage, coupled with the ongoing shift to digital payments, is the reason both stocks have handily crushed the S&P 500 over the past five years. 

If you want to invest in crypto, do yourself a favor and choose the safer, but still lucrative, option. Consider these top fintech stocks instead. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.