Dogecoin (DOGE -7.57%) has been on fire lately. The price of a single token has skyrocketed by more than 3,000% in the last year, and it's up by 25,000% over the last five years. Most assets never see those kinds of gains, but that doesn't make Dogecoin a smart investment.

Cryptocurrencies in general come with great risk and volatility, and even among them, Dogecoin skews toward the riskier side of the spectrum. Rather than putting money into such a highly unstable asset, investors looking to cash in on the cryptocurrency craze should consider buying PayPal (PYPL 0.64%) instead.

Dogecoin: Tulip-mania

Despite its recent massive gains, there are several problems with Dogecoin. One, in particular, should give investors pause.

Digital currency concept design.

Image source: Getty Images

The potential supply of Dogecoin is infinite. Unlike Bitcoin, which will be limited to 21 million tokens total, there is no upper bound on the number of Dogecoin tokens that can be mined. As long as miners keep building the blockchain, more will be created. In fact, there are already 129 billion tokens in existence.

That's a problem because eventually, the supply will exceed the demand. At that point, economic theory suggests prices will fall. To put that in context, precious metals like gold and platinum have high values because they are scarce. But what if gold and platinum were everywhere? They wouldn't be worth much.

During one of the most famous market bubbles of all time, tulip bulb prices skyrocketed in Holland in the 1630s. Fueled by the overwhelming popularity of the flowers, at one point, a single bulb sold for as much as $750,000 in today's money. Obviously, that didn't last, and the so-called tulip-mania bubble burst after a few years.

The point is this: Just because the price people are trading Dogecoin at has increased by a factor of 30 in the course of a year, that doesn't mean it's actually worth anything like that much. Sometimes, people get carried away.

PayPal: A better buy

PayPal—unlike Dogecoin—offers a clear-cut investment thesis: Digital payments are becoming more popular with people and businesses around the world, and this fintech company provides the tools that consumers and merchants need to participate in the digital economy. As that trend continues to evolve, PayPal and its shareholders will be well-positioned to prosper.

Moreover, the company's global network gives it a significant advantage over its rivals (another thing Dogecoin conspicuously lacks). As more merchants join its network, it becomes more valuable for all consumers, because they can spend the money in their PayPal accounts in more places. The same is true in reverse: As more consumers set up accounts on the network, it becomes more valuable for all merchants.

This network effect has driven significant growth for PayPal in several important financial metrics.

Metric

2017

2020

CAGR

Active Accounts

229 million

377 million

18%

Revenue

$13.1 billion

$21.5 billion

18%

Free Cash Flow

$1.9 billion

$5.0 billion

39%

Source: PayPal SEC filings. CAGR = compound annual growth rate.

PayPal is also establishing itself as a key player in the cryptocurrency economy. Last year, the company announced that users would be able to buy, sell, and hold cryptocurrencies like Bitcoin directly from the PayPal and Venmo apps.

More recently, PayPal launched its Checkout with Crypto service, enabling consumers to fund their purchases with cryptocurrency. And eventually, it plans to bring this functionality to all of its 29 million merchants. That makes it the first major payment processor to directly power cryptocurrency transactions.

If cryptocurrencies truly become mainstream, PayPal should benefit in a big way. But even if they recede into a small niche market or disappear completely, it will still have a thriving business. In other words, this fintech company is a safer investment than Dogecoin, yet it still offers the potential for big gains. That's why investors should consider adding PayPal to their portfolios.