Apple is touting its new credit card as a major step forward in the realms of convenience and privacy. But the Apple Card also comes with a major catch: you need an iPhone to pay your bill.

While most major credit cards give users the ability to pay online through a personal bank account or multiple other methods, the Apple Card requires holders to use the Wallet app on the iPhone to make a bill payment.

The Apple Card is the latest example of the tech giant’s closed system strategy in which Apple products function only or primarily with the company’s other products or services, locking consumers into an all-Apple universe.

The card also arrives at a time when iPhone sales continue to decline. The iPhone still accounts for almost half of Apple’s total revenue.

Apple says on its official Apple Card site that users must enter their personal banking information into the Wallet app, or use Apple Cash, in order to make card payments. Users also need to use the Wallet app to see their payment history.

In the event of a lost iPhone, Apple recommends two courses of action, according to a recent Buzzfeed report. The cardholder can use an iPad or other iOS device to access the Wallet app, or call Apple Support, which will connect the customer to Goldman Sachs, which is a partner with Apple on the card.

Apple is expected to launch Apple Card this month. The card is designed to live entirely in the Wallet app, though users will also receive a physical credit card.

The card, which uses MasterCard’s payments network, is Apple’s latest attempt to diversify its revenue streams as iPhone sales continue to decline. Last month, Apple reported iPhone sales of $26 billion for the most recent quarter, down 12 percent from $29.5 billion in the year-ago period.

Apple is also making a major investment in the entertainment industry, through Apple Studios and its new streaming service, Apple TV+.