Samsung, LG have sold you their little black dress. Now they want you to accessorize

It's no longer just a phone you're buying. You're also getting the keys to a walk-in wardrobe of devices.

That was a key trend to emerge Sunday as Samsung and LG unveiled their latest superphones, a day before the Mobile World Congress conference kicks off here in Barcelona. Although the companies' flagship products received upgrades, it was clear that's no longer enough. Instead, there was a lot of talk about capabilities that extend beyond the phone.

Samsung talked up its Gear 360 virtual reality camera, which joins a spring collection of devices such as the Gear VR headset, Gear S2 watch and TVs that can be linked to its newest phones, the Galaxy S7 and S7 Edge. The company is working to mirror the display of its phone on a Samsung refrigerator screen too.

LG took the concept a step further, offering companion pieces like a camera grip and souped-up audio attachments that can be swapped into the LG G5 phone itself. LG, which also released a 360-degree video camera and a rolling robot, promised additional modular attachments.

Even Sony got into the accessory game, expanding its Xperia line with a "smart" Bluetooth earpiece and showing off conceptual images of a small, GoPro-like camera, projector and personalized assistant that were arguably more exciting than its phone news (a new family of phones called Xperia X).

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Bringing back the excitement

The emphasis on different capabilities and buzz-worthy accessories speaks to the lack of excitement consumers now feel about phones themselves and to the new ways these companies are working to get you jazzed again. Think of it as the next step for the digital-era equivalent of the little black dress. The smartphone is largely fixed, a classic. Now its makers are less focused on software and more on adding capabilities via hardware -- in other words, accessorizing. But instead of a statement clutch or a sharp pair of heels, it's a virtual reality camera or a drone.

"We're pushing the frontier to go beyond the phone," Justin Denison, Samsung senior vice president of strategy and marketing, said in an interview in San Francisco before Mobile World Congress.

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Let's face it. You probably aren't feeling the need to upgrade your phone, despite the flashy new wide-angle camera on the LG G5 or the return of the waterproof body in the Samsung Galaxy S7. Designs have largely settled on slim, glassy rectangles encased in plastic or metal, and they all seem to do the same things. That's a problem for the mobile industry, with phone growth slowing to a crawl, according to Gartner.

"Most of these phones look alike now," Lopez Research analyst Maribel Lopez said. "It's becoming harder to differentiate."

LG put it more bluntly. "We don't see excitement anymore," Juno Cho, president of the mobile business, said at the company's phone unveiling.

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03:09

Tying it all together

Touting a range of devices that play well together has long been one of the strengths of iPhone maker Apple. Now Samsung, LG and, to a lesser extent, Sony are taking their turns.

It has been harder for companies that build phones using Google's Android software, the most popular mobile operating system in the world, to do the same because they don't control all of the pieces. That's why many of the accessories don't use Android.

Samsung's Gear VR headset and Gear 360 virtual reality camera require a Galaxy phone to run. The Gear S2 smartwatch uses the company's homegrown Tizen software.

LG's modules are largely physical components, such as speakers, drone controls or a bulky camera grip, and don't need software.

While this is an effort to position the phone as more than a phone, a lot will depend on price. It's telling that neither Samsung or LG were forthcoming on what you'll have to pay for their new accessories. The $99 Gear VR, however, comes for free if you preorder one of Samsung's new phones.

LG said there is an opportunity for its carrier partners to bundle some of the modules with the G5. You're likely to see some of these products pop up in carrier stores, since accessories tend to be a profitable business.

Now it's up to you. Your willingness to buy into these products -- or not -- will determine whether this is long-term trend or a fleeting gimmick.