There are many good reasons to be cautious if you're thinking about an investment in bitcoin. The cryptocurrency is highly volatile, for one, and its long-term usefulness as a virtual currency is still an open question.

You can find far less risky investment opportunities among individual stocks, whose returns ultimately depend on more predictable metrics like sales growth and profitability.

Below, Motley Fool investors highlight three such options that look attractive right now. Read on to see why you might want to consider picking up shares of Facebook (NASDAQ:FB), Roku (NASDAQ:ROKU), or Starbucks (NASDAQ:SBUX) before shelling out for bitcoin.

A chart of returns for various cryptocurrencies

Image source: Getty Images.

An oversold stock with a huge moat

Jeremy Bowman (Facebook): Bitcoin investors are no strangers to controversy. The popular cryptocurrency has been a hot topic of debate among investors, economists, and regulators in recent years, amid speculation over whether bitcoin will ever become a widely used currency.

In the stock market, Facebook has recently courted a whirlwind of controversy due to the Cambridge Analytica scandal, which has pushed the stock down more than 10%. However, the actual fallout from the complicated incident is unclear, and I think the sell-off sets up a buying opportunity.

The uproar over Cambridge Analytica's misuse of Facebook data could lead to increased scrutiny from regulators, but it's unlikely to affect the behavior of many Facebook users; they spend on average 50 minutes per day on the company's properties, which include Instagram, Messenger, and WhatsApp.

The company's network effects are incredibly strong. There is simply no adequate substitute for its platforms that would allow users to readily share life updates, photos, messages, invitations, and news items, among other things. And that set of network effects has built a wide economic moat with operating margin near 50%, meaning Facebook can easily afford to make any adjustments that regulators may impose.

Now trading at a price-to-earnings ratio of 30.6, the stock is cheaper than it's ever been. And the company still has a number of promising growth avenues ahead, including international users, Instagram, and its messaging apps. If you think that Facebook users will soon forget about the latest scandal once the news cycle moves on, now looks like a great time to buy.

Tune into this opportunity

Rich Duprey (Roku): Shares of online-streaming device maker Roku may not be as discounted as the value of bitcoin these days. But with their depressed price, and Roku's future growth opportunities, the stock is a better buy than the cryptocurrency.

A family watching television

Image source: Getty Images.

While Roku's hardware segment remains the biggest source of revenue, it's the content platform that is growing fastest -- and offers the best opportunities for taking the streaming-video service to the next level and beyond.

Roku just announced that its Roku Channel will appear on smart TVs from Samsung. This will be the first time Roku's ad-supported content can be seen on something other than a Roku device. It also points the way to how the service will be using its vast content library to challenge both Netflix and no easy task, to be sure, and it may require Roku to eventually get into producing original content like its rivals do. But Roku's devices have the largest market share, with a 37% installed base, and it's one of only two streaming-media services that saw its share increase.

Roku is still losing money at the moment. But its platform segment is vastly more profitable than hardware, with gross margins in excess of 74% -- so continuing to monetize the asset should get it into the black fairly quickly, and ought to catapult its stock higher. There seems a lot less risk involved in betting on this streaming-media company than on the direction bitcoin's value is going to take.

Caffeinate your portfolio

Demitri Kalogeropoulos (Starbucks): Starbucks stock has created many millionaires since its 1992 initial public offering, but that success hasn't attracted anything like the media attention that bitcoin's volatility has drawn. Yet if I had to bet on which investment can beat the market from here, it wouldn't be a close call.

Coffee beans and a cup of coffee

Image source: Getty Images.

Sure, Starbucks is struggling with unusually weak growth in its core U.S. market. Poor merchandising over the holiday season might mean the retailer will land just shy of management's sales targets for the second straight year, too.

But the coffee titan has no shortage of expansion opportunities. It is opening stores in China at a rate of one every 15 hours, with 1,800 new locations set to launch between now and 2021. The U.S. segment stands to benefit from rising food sales, which recently hit a new record for Starbucks at 21% of the business. There's also a big opportunity to drive afternoon traffic with new iced and cold-brew drinks.

Even if a growth rebound takes longer than expected at Starbucks, investors can feel confident in riding out volatility while owning this highly profitable market leader. You can't say the same thing about the value of a bitcoin holding.

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.