There's a clear trend toward cashless payments all over the world. While cash isn't likely to go away entirely -- at least not anytime soon -- it is continuously becoming easier, cheaper, and generally more desirable to use card, contactless, and mobile payments for everyday purchases.

Financial technology companies all over the world stand to benefit from this trend, often referred to as the War on Cash. Square (SQ 0.71%) is one of them. Could this payment processing and consumer finance technology giant be a smart way to start investing in this exciting and long-tailed growth trend?

A customer making a purchase with a Square card reader.

Image source: Square.

Square has evolved dramatically over the years

Square was founded as an efficient and inexpensive way for small businesses to accept card payments. The company's original product was the small square-shaped card reader that worked with the merchant's smartphone.

Since then, Square has evolved into quite the financial ecosystem. Its core payment processing business is still going strong, but the company has graduated into more complex hardware systems. More than $100 billion in annualized payment volume now flows through its terminals. In addition, Square Capital has made billions in small business loans, doing so with a more seamless and data-driven process than most alternatives.

Square's growth on the personal finance side has been even more impressive. The company's Cash App now has 30 million active users, more than quadrupling since the end of 2017. In addition to being able to send and receive money, Cash App users can get a debit card linked to their account, have their paychecks directly deposited, trade stocks, and buy bitcoin.

Could there be more room to go?

For one thing, there could still be tons of room to grow in Square's existing business. Card payments are expected to reach $45 trillion in worldwide volume by 2023, and Square currently has about 0.25% of this amount. What's more, Visa (V 0.09%) has an estimated $185 trillion global payments opportunity in person-to-person, business-to-business, and international money transfers, all of which are or could be functions of the Cash App.

In addition, Square plans to keep rolling out new verticals. On the business side, Square just recently launched Online Store, which helps merchants set up websites, provide curbside pickup, and build out an omnichannel presence. On the personal side, Square's leadership has said that it wants the Cash App to offer what customers would ordinarily go to a bank for. That means high-yield savings accounts, personal loans, mortgages, and auto loans could eventually be rolled out to Square's massive user base.

Square is still in the early stages of monetizing its Cash App users. With a rapidly growing user base that's already 30 million strong, there's tremendous potential to boost revenue from this side of the business.

Is Square still a good War on Cash stock to buy?

Hovering at about 12.5 times trailing-12-month revenue and having not yet achieved consistent profitability, Square isn't a cheap stock by any definition of the term. If you want a War on Cash stock that's already consistently profitable and more mature, Visa or Mastercard (MA 0.30%) could be more appropriate for you.

However, if you're looking for long-term growth, Square might be a good fit. With a great track record of innovation, a massive addressable market opportunity, and 64% revenue growth over the past year, Square could be a smart stock to start your War on Cash basket with.