Lost in the news that Google will offer a checking account next year is the implication it has for one of the fiercest rivalries in the tech world.

The two dominant operating systems for mobile phones — those supercomputers most of us carry around all day — are Apple's iOS and Google's Android, which together run most of the planet's 3 billion-plus smartphone devices.

Google signed a deal last month with Citigroup to develop a checking account that will be linked to Google Pay as early as next year, according to a source with knowledge of the discussions. Apple launched its first iPhone-integrated credit card with Goldman Sachs in August.

While the starting points are different, both are new consumer finance products linked to digital wallets embedded in respective Apple or Android phones. Whether it's Apple Pay or Google Pay, the real battle will be to keep users locked into ever-growing payments ecosystems. Doing so will help the tech giants capture more of the fees and information now being given up to banks and fintech startups.

"Everyone wants the payment to happen through their device, because if it's effortless it will entrench you in their ecosystem," said Gerard du Toit, banking consultant at Bain. "The information is valuable for Google in particular; if they are able to connect a specific purchase to advertising, there's immense value in that."

Like the Apple Card, the Google account — referred to as a "smart checking account" by the search giant — will come with budgeting tools, the company said in a statement.