Image source: Motorola.

Apple's (AAPL -1.04%) next iPhone is likely to ship with a faster processor and better camera, two features that should help the Cupertino tech giant remain on top of an increasingly competitive smartphone market. Yet the phone may be defined more by what it lacks than what it offers.

Apple is widely expected to ditch the 3.5mm headphone jack in favor of Bluetooth and lightning-based audio on the next iPhone. The move will be controversial. The 3.5mm port is tried and true, and almost every set of headphones currently in existence makes use of it. Consumers who upgrade to the latest iPhone may also need to upgrade their headphones, or make use of a cumbersome dongle.

But Apple's competitors have already beaten it to the punch. Lenovo's forthcoming flagship, the Moto Z, has no headphone port. It goes on sale later this month, many weeks before the next iPhone, and could provide some sense of the backlash a headphone port-less iPhone will generate.

A USB-C dongle in every box

At first glance, the Moto Z looks like a pretty typical Android flagship. There's a 5.5-inch display, speedy Snapdragon 820 processor, and plenty of RAM. It has some interesting features, most notably support for swappable, modular backplates, but the one thing it doesn't have is a 3.5mm headphone port. It has a single USB-C port located on its lower side. That port is used to charge the device, but it can also send out an audio signal.

Included with every Moto Z is a small USB-C-to-3.5mm adapter. Bundling it with the phone is a consumer-friendly move, but it's not a perfect solution: Moto Z owners who wish to use traditional headphones will have one extra cord to worry about -- one more thing to carry around, one more thing to lose. And even with the adapter, the situation isn't perfect: You can't charge the phone and listen to headphones at the same time. Ultimately, some may find the burden too much and opt for a different handset entirely.

In general, reviewers haven't been overly impressed with the Moto Z, but they haven't written it off entirely, either. Most of the criticism has stemmed from its excessive price tag, mediocre camera, and Motorola's poor track record of delivering timely software updates, with its missing headphone jack serving only as a modest knock on the device rather than an outright dealbreaker.

"The Moto Z...has some good things going for it, but has just as many in the average get an average camera, average battery life, [and] a phone that isn't that much fun to hold," wrote Droid Life's Kellex. "It's not as polished or sculpted a phone as Samsung's Galaxy S7. Nor is its camera as good. Nor is it waterproof. Nor does it have a headphone jack...the [Galaxy S7] is probably a better phone," wrote Wired's David Pierce. 

Is Apple about to make a mistake?

Bluetooth audio has improved tremendously in recent years, and Bluetooth headphones can now be had for as little as $20. Unfortunately, Bluetooth headphones have their own internal batteries, which means their owners need to remember to recharge them. They also have to be paired and unpaired, which can be a confusing, and at times difficult, process. But the upside is just as significant: There's no cord to get in the way.

In the U.S., the Moto Z will (at least initially) be restricted to Verizon, launched as the latest installment in the long-running DROID series of phones. That will restrict its market to Verizon subscribers. Moreover, Motorola has -- for many years -- been a third-tier smartphone-maker, with its U.S. market share hovering around a modest 5% (compared to upwards of 40% for Apple).

That will make comparing the relative success of the Moto Z with that of the iPhone difficult. Still, its existence should benefit Apple. If Apple does ditch the 3.5mm port, it won't be alone. Other Android OEMs could follow Motorola, and in time, consumers could come to view the 3.5mm as a relic of the past. Bluetooth headphones should enjoy rising popularity, and increasing ubiquity, making the prospect of a headphone jack-less iPhone far more palatable.