Dogecoin may be one of the best examples of a highly speculative cryptocurrency. Back in 2013, Dogecoin was created as a joke based on a popular meme. Now, it's the 11th-largest cryptocurrency by market cap. 

But while the coin has become enormously popular -- thanks in part because Tesla Chief Executive Officer Elon Musk likes to tweet about it -- there are lots of other cryptocurrencies out there that have real value and that also could make great long-term investments.

Instead of betting on one of the riskiest coins out there, investors may want to instead focus their attention on Bitcoin (BTC -3.58%), Ethereum (ETH -8.81%), and Cardano (ADA -21.63%). Here's why. 

A dog with its eyes closed.

Image source: Getty Images.

1. Bitcoin

There shouldn't be any surprise why Bitcoin is on this list. As the first cryptocurrency, Bitcoin has the first-mover advantage in the digital token market. 

Bitcoin has not only become the most valuable cryptocurrency by market cap, but it has also become a gauge for the rest of the crypto market. What this means is that when the price of Bitcoin rises or falls, it typically takes a lot of other coins along for the ride.

This shows just how influential Bitcoin has become, but it's certainly not the only reason investors should consider owning it. Bitcoin is also viewed by many inventors as a store of value, similar to gold.

Store-of-value investments refer to items that tend to maintain their value over time, mainly precious metals. Goldman Sachs recently estimated that Bitcoin has about 20% of the entire store-of-value market and that the percentage will likely increase in the coming years. 

Which leads us to the final reason Bitcoin could be a compelling investment: It continues to gain acceptance by banks and financial institutions. Morgan Stanley and Goldman Sachs now let some of their clients invest in Bitcoin futures, and other banks are considering adding some form of Bitcoin investing to their investment services.

2. Ethereum 

If you follow the crypto market even a little bit, then you've likely heard a lot about Ethereum and its Ether token. For some people, the fact that Ether is the second-most valuable digital token after Bitcoin is enough for them to consider owning it, but there is one much more compelling reason: its blockchain. 

The Ethereum blockchain is the go-to technology for developers looking to build decentralized finance (DeFi) apps. DeFi is the catch-all term for financial technology that allows people to borrow, lend, buy, and sell without the need for centralized financial institutions like banks. 

DeFi could be transformative for many markets, and Ethereum is at the heart of it all. Already, its blockchain is used in many popular non-fungible token (NFT) markets. That's important because the burgeoning NFT market is already worth a staggering $41 billion. 

In addition to its potential in DeFi, traditional financial companies are also embracing the Ethereum blockchain for their own uses. For example, Mastercard recently partnered with a software company that uses Ethereum so that the two companies could help build "the future of commerce," and Visa expanded its services late last year to incorporate processing cryptocurrency payments directly on the Ethereum blockchain.

3. Cardano 

And then there's Cardano and its ADA coin. Although less well known than Bitcoin and Ethereum, Cardano is still one of the top cryptocurrencies by market cap, coming in sixth place right now at almost $40 billion.

What's intriguing about Cardano is that it could end up being one of the fastest blockchains out there. The value of many blockchains is due, in part, to how efficiently they can process transactions. 

For example, right now Cardano can process 250 transactions per second, compared to Ethereum's 30 at most. And it's only going to get faster. A lot faster, in fact. 

Cardano is on the third phase of a five-step plan to expand its blockchain capabilities. And when it reaches the fourth step, in which it scales its system, it could boost the number of transactions the blockchain can process to 1 million per second. 

This expansion could happen later this year or in 2023, so investors will need to be a bit patient. But when Cardano scales its blockchain, it could become an even bigger competitor to Ethereum. 

Remember this 

Although these three cryptocurrencies have more real-world uses than Dogecoin, investing in them still comes with a significant amount of risk. Before you dive into buying cryptocurrencies, make sure you're ready to stomach some volatility, and, as always, don't invest any money that you might need over the next several years.