Amazon's (NASDAQ:AMZN) Prime Instant Video took a major step forward on Tuesday: Owners of Android-powered tablets and smartphones are now able to access Amazon video content on their mobile devices.

Previously, if Amazon Prime members wanted to watch Prime Instant Video on a tablet or smartphone, they were limited to the the iPhone, iPad, Amazon's own Kindle Fire tablets, or the Fire Phone.

This may seem like a relatively minor change, but given the large and growing number of Android-powered tablets and smartphones, it could have a significant effect on Amazon Prime Video, making it much more attractive, and a more capable alternative to Netflix (NASDAQ:NFLX).

Amazon is building a better Netflix competitor
In a broad sense, Netflix has numerous competitors, but in terms of Internet video, Amazon Prime may be its fiercest rival. The Internet retailer has certainly stepped up its commitment to Prime Instant Video in recent months, pouring millions of dollars into original programming, and signing a major content licensing deal with HBO.

But that content means little if Amazon's customers can't access it. To be fair, Amazon Prime Instant Video hasn't been inaccessible -- in addition to Apple's mobile devices and Amazon's own tablets, Amazon Prime content can be viewed on traditional PCs, most modern gaming consoles, Roku devices, and Amazon's FireTV.

Still, the lack of Android support has been an obvious oversight. Android powers the majority of smartphones used in the U.S. (more than 51% according to recent numbers from ComScore) and a fair share of the tablets. In April, online ad network Chitika estimated that Samsung's Galaxy tablets accounted for more than 8% of North American tablet web traffic -- given that Samsung's devices run Android, those users couldn't (before Tuesday) watch Amazon Prime Video on their tablets. They could, however, use their tablets to watch Netflix, and many of them probably do. Last year, Nielsen noted that 15% of Netflix subscribers used the service on their tablet, and more than 20% watched Netflix video on their smartphone.

In the sense that Amazon Prime Video competes with Netflix for subscribers, bringing it to Android makes it a stronger alternative. Netflix has consistently, and repeatedly, stressed its commitment to getting its service on every conceivable Internet-connected video platform. In recent letters to shareholders, Netflix's management has discussed at length its intentions to bring the Netflix app to as many new smart TV platforms as possible.

A case against the Kindle Fire
With access being so crucial, Amazon's avoidance of Android may have been motivated by a desire to defend its own rival products. Its Kindle Fire tablets, for example, with the ability to access Prime Instant Video, had an obvious advantage over similarly priced, Android-powered alternatives. The same could be said of the Fire Phone, whose promotional materials have centered around the included year of Amazon Prime, and the Internet video that entails.

Bringing Prime Instant Video to Android lowers the competitiveness of Amazon's own hardware, but at this point, the trade-off may be worth it.

Unfortunately, Amazon doesn't disclose its device sales, but there's growing evidence that its products are under pressure. Earlier this month, the company made headlines when it slashed the price of its Fire Phone after only two months on the market. Amazon's Kindle Fire tablets, meanwhile, were largely responsible for establishing the 7-inch tablet form factor, but have fallen in popularity as more capable Android rivals have appeared on the market. According to Chitika, the web traffic from Amazon's tablets fell more than 1% this year.

Amazon is taking video seriously
With a slate of new Amazon originals, and an app for Android (finally), it appears that the Internet retailer is taking Prime Instant Video far more seriously than ever before. For Amazon, that could result in more Prime subscribers, who are generally more lucrative customers, though it could certainly cannibalize sales its own products in the process.

For Netflix, it means more competition -- when it comes to streaming video services, owners of Android-powered devices finally have a choice.

Sam Mattera has no position in any stocks mentioned. The Motley Fool recommends Amazon.com, Apple, Google (A shares), Google (C shares), and Netflix. The Motley Fool owns shares of Amazon.com, Apple, Google (A shares), Google (C shares), and Netflix. 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.