The tech news has spent a lot of time over the last few months, explaining in detail why it feels that the relatively newly announced Firefox OS doesn't matter. Many of the arguments center on the fact that we already have a well-established, open-source (mostly) mobile operating system in Android, so why on earth would Mozilla be attempting to get into this game? The problem these articles all seem to have is that they're focusing on two incorrect assumptions... The first is that this being open-source matters and the second that the developed world is the target.
Both of these faulty assumptions have essentially the same answer, namely that Firefox OS, if its design philosophy holds true to Mozilla's history, it will be the lowest-cost provider of a robust, fully-supported platform. Lets unpack that statement just a bit as you might be wondering exactly how that answers the two faulty assumptions.
Open source software is generally thought of as being free; free to download, use and distribute however you see fit. While that is an oversimplification of what open source really is, the important part from the perspective of most users is the free part. Firefox OS isn't something that users will download however as it will be the operating system and primary interface for a hardware device. For device manufacturers however, especially those with a significant presence in emerging markets which require extremely low cost devices, Firefox OS has some significant advantages, even over Android.
For the hardware device manufacturers, Firefox OS's low system requirements and focus on browser technologies should mean a device that is easier to produce and cheaper to manufacture. This could lead to higher sales in parts of the world that have significantly lower income. Price really does matter, especially to those with a lower overall income. A fully-functional smartphone enables access to many new opportunities for the consumer, so getting that device in as many hands as possible makes a lot of sense. A lower price makes that possible.
That's not to say that you can't make an Android device that retails for the same price as one running Firefox OS; you probably can. The difference here is what it takes to produce the device. We're talking cost versus revenue. If Firefox OS becomes cheaper to produce because of lower system requirements and easier implementation of the OS than Android, device manufacturers will make a larger profit from selling a Firefox OS device than an Android device. If customers in emerging markets don't see Android and Firefox OS as significantly different, then the device manufacturers would be foolish to not invest resource in producing Firefox OS devices.
To develop apps for Android, you need a device capable of running the Android SDK. For Firefox OS, you need a web browser and a text editor. In the emerging market, where the primary computers of most individuals will be their smartphone, having a device that can author its own software and still fit in your pocket can be a significant advantage.
Much of this is speculative, both on my behalf and on behalf of those who are arguing that Firefox OS is irrelevant. Time will tell which is true. The point here is not to write off the work of the Mozilla team just because you prefer that the world adopt a different operating system that already exists (Android) as many of the tech writers have already done. I wish the Mozilla team the best and hope they succeed. Having another feature-rich, price competitive alternative in the market is nothing but a good thing.