Apple (NASDAQ:AAPL) has always largely ceded the iPhone accessory market to third-party partners.

The company makes an array of cables, cases, and other items, but in most cases its own branded items are dramatically more expensive than licensed alternatives. Even a simple Lightning to USB charging cord cost $19 for the Apple-branded version while Amazon.com (NASDAQ:AMZN) sells a comparable model under its Basic brand for $6.99.

Though the overall smartphone accessories market was pegged at $21 billion way back in 2012, according to ABI Research, and it has certainly grown since then, Apple has largely sat on the sidelines. The company has not been an innovator in the iPhones accessories space offering basic, albeit elegant takes on basic items at premium prices.

That makes it somewhat peculiar that the company has decided to release its first smart battery case for iPhone 6s. It's an interesting move by Apple that could help it keep a larger chunk of accessory revenue for itself, but the device looks be meeting some initial skepticism.

What has Apple created?
The company somewhat surprisingly introduced a $129 Smart Battery Case (many reports call it a $99 case, but Apple is currently selling it for $129) that works with both iPhone 6 and iPhone 6s, but not the larger Plus models of either device. It's available in white or grey. The case has a "soft microfibre lining," according to Apple, which the company said helps protect your phone. It also has what the company calls an "elastomer hinge design" that "makes it easy to put the case on and take it off again."

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The case is not that big, but it has an odd design. Source: Apple

The exterior is made of silicone making the case soft or at least not rigid metal. It does not require a separate charging cable -- it works with the existing Lightning connection -- and it offers, "increased talk time up to 25 hours, Internet use up to 18 hours on LTE, and even longer audio and video playback," according to Apple's product page.

Perhaps the most noticeable feature is that the Smart Battery Case does not have a flat profile. Apple has chosen to give it a bump, which has not been well-received by some reviewers.

"It looks like the iPhone is carrying a tiny backpack, or maybe ate a wallet, or has a geometrically precise tumor, or is attempting to sneak a jumbo pat of butter out of a fancy restaurant," wrote Wired's Brian Barrett.

Apple has also chosen to not give the case an on button. Many of its competitors let users choose when to activate their extra battery power. In Apple's case the company has decided to have the case activate as soon as it's put on a phone. If both the iPhone and the case have a 100% charge the phone's battery is depleted first, then the case's.

That's really only a minor negative, but an on/off switch is offered on a number of cheaper rivals.

Why does this exist?
Perhaps the most peculiar part of Apple's decision to enter this market is that it has not, by most estimations, released a top-tier device. The reviews did not, for the most part, hate the Smart Battery Case, but a number of reviewers made it clear this is not a best-in-class product.

"Just know that from a pure performance and even a design perspective, Apple's effort is not the best you can get," wrote Lauren Goode at The Verge.

Joanna Stern of The Wall Street Journal liked it more, but noted that that "with a third-party case, you can get twice as much power for half the cost."

That's really the issue here. Apple has built a "meh" battery case and Amazon already shows dozens of those available, some for under $40. That's not to say that Apple's case is not superior to its low-cost competitors, but when you can buy a case for $35.99 that gets four stars from Amazon users with over 3,700 reviews, it's hard to see the play here.

Apple has built its business on delivering best-in-class devices that people are willing pay premium prices for. It has the price part down, and the device is functional, even pretty good, but it's nothing special.

Daniel Kline owns shares of Apple. He uses an iPhone 6s Plus and never remembers to charge his off-brand battery case. The Motley Fool owns shares of and recommends Amazon.com and Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.