"The tech giant prevented other companies from offering applications that compete with Apple products like its digital wallet, which could diminish the value of the iPhone, the government said."
They literally offer APIs for any company to integrate with their wallet. As a consumer, I wish more apps would do so instead of half-heartedly implementing their own thing.
Antitrust law is there to protect consumers, not your business model.
As a consumer, I don't want to have to use 23 different wallet apps on my phone but am happy to have one secure implementation that's easy to use. You could argue that Apple Pay imposes lots of processing fees that will raise prices for consumers as vendors pass on processing fees to consumers and that prices would be lower if there was more competition, but I highly doubt this is the case in reality as Apple Pay processing fees are the same as regular payment processor fees for merchants.
They literally offer APIs for any company to integrate with their wallet. As a consumer, I wish more apps would do so instead of half-heartedly implementing their own thing.