Success for the Department of Justice's ambitious antitrust lawsuit against Apple could alter how iPhone owners use their phones and transform the workings of Apple's interconnected system of products.

Why it matters: Whether you see those changes as good or bad will likely depend on whether you prefer to customize your phone experience or leave it on autopilot.

The DOJ case lists a broad range of anticompetitive practices by Apple. Per the suit, the company:

• uses its control of the iPhone App Store to "undermine" super apps and cloud-streaming apps;
• uses its APIs to "undermine" competitors in messaging, smartwatches and digital wallets;
• and uses the terms of its contracts with developers and others to "obtain, maintain, extend or entrench a monopoly."

The big picture: Supporters of the DOJ suit believe a win would spur innovation and lead to better, cheaper products.

• If developers don't have to pay a big slice to Apple every time someone buys their app, they could pass that cost savings on to the consumer. The same could be true for fees financial institutions currently pay on Apple Pay transactions.
• Government officials argue that users would be better off with a looser Apple ecosystem that gives more flexibility to different apps and services operating on Apple's products.
• The suit aims to limit the rules that Apple can impose on the development of third-party products without restricting Apple's development of its own products and services.

That's a pitch to the power users, tech aficionados and software developers who chafe at what they see as Apple's paternalistic control and want more control over their iPhone.

• If you're one of these people, then in the future you might tap and pay with your iPhone or Apple Watch using a payment app that isn't Apple Pay. You could more easily tap to pay with reward points or loyalty points.
• You might also be able to buy a smartwatch that Apple didn't make and get all of the same features that currently exist on the Apple Watch.
• Apple could be forced to allow cloud streaming apps into its app store, which means that gamers could have more options to stream more than one game through the same app (in the same way we stream more than one show or movie in video streaming apps).
• You might be able to choose your own default messaging app, and you could choose one that uses end-to-end encryption, no matter who you're messaging. (Currently, end-to-end encryption doesn't work if you're using iMessage to communicate with someone using an Android.)

Fun fact: If the DOJ wins this case, your messaging bubbles might all be the same color at last, ending Apple's long practice of displaying non-Apple messages in green rather than blue.

Yes, but: If you're the sort of person who rarely customizes phone settings, changes defaults or tries out new apps, a DOJ victory could end up at best making very little difference, and at worst adding new confusions and frictions to your phone use.

The other side: Apple warns that a government victory would imperil or wreck the seamless and secure experience its users expect, and opening the App Store's doors more widely would invite uncomfortable tradeoffs.

• That could be particularly difficult for parents who rely on Apple's proprietary family sharing, family safety and screen time features in apps.
• Apple settings allow parents to designate which apps a child can download, how long they can use them, and whether or not apps can be shared with other family members.
• Approved apps must include code that ensures that these features work, but if you can download an app from anywhere, family sharing and screen time features might not work the same way.

Caveat: If the DOJ succeeds in forcing Apple to open up the App Store, that could leave room for alternative app stores designed specifically for children (or adults).

Between the lines: The DOJ suit doesn't paint a specific picture of a world in which it has prevailed and forced Apple to change its behavior.

• That will make it harder to persuade a judge or the public that an alternative world would be better.

Reality check: The case is likely to take years to resolve. By the time it's settled, we might be using our smartphones in very different ways.

What we're watching: Apple will fiercely defend itself against the antitrust suit — and that starts with a campaign to get the folks who love the iPhone to protect what they love about it.