Given that Sharp recently announced a 5.5-inch 4K display for mobiles, we can assume smartphones are entering an age of unprecedented overkill. True as that is, there's actually a useful target for this pixel-packed product: making virtual reality finally feel real.

There's little question Sharp's small ultra-high resolution IGZO displays will wind up in smartphones someday; the size fits snugly with increasingly popular phablet devices like the iPhone 6 Plus. (Sharp reportedly is one of the companies supplying Apple with displays). And there's clearly marketing appeal to the 4K display claim; it's more, so it must be better!

That's unlikely to be the case in practice. Sharp's latest offering has a walloping 3850x2160 resolution, a total of 806 pixels per inch. That's roughly twice the resolution of the 5.5-inch iPhone 6 Plus and 5.7-inch Galaxy Note 3, two devices on which you're unlikely to spot a discernible pixel without a magnifying glass or a generous imagination.

From a typical viewing distance you'd only be able to resolve about half the resolution a 5.5-inch 4K display would provide, says Dr. Raymond Soneira, president of DisplayMate Technologies. "In many/most cases the additional sharpness and resolution are lost for most people, most applications, and most viewing conditions" he said in an email.

In other words, we're already pretty much maxed out.

That's not to say you should dismiss a 4K smartphone display altogether; it'll have ancillary benefits, Soneira says, not the least of which is making it easier to rescale the Full HD content that will become standard as content creators fully embrace 4K. And those gifted with peregrine-esque eyesight will be able to discern subtle differences in detailed graphics and tiny text if they want to blow an afternoon doing so.

None of which seems particularly worth it, especially when you consider the battery-hoovering required to keep all those pixels lit. 4K smartphone displays will look great on signage (Ultra Retina HD, anyone?) but would be a giant shrug in practice for everyone but companies making battery cases.

That's fine, though. The main beneficiaries of Sharp's resolution revolution aren't smartphones, anyway.

A Virtual Virtue

If you haven't tried a virtual reality headset like the Oculus Rift or HTV Vive yet, the first thing to know is that you're in the vast majority; despite years of promising demos, there's no high-end, head-mounted virtual reality display on the market yet. The second thing you need to know is that however impressive the first-hand accounts you've read are, these devices have a long way to go.

A 5.5-inch, 4K, 806 ppi display is going to help get them there fast.

Brian Blau, an analyst with Gartner who focuses on consumer technology, including virtual reality, says the VR benefit of putting ultra-high resolution in virtual reality head-mounted displays will be immediate and obvious.

"If the display resolution isn't high enough, you tend to see the individual pixels," explains Blau. This sounds like an obvious point, but it's exacerbated by the particular quirks of virtual reality technology. Most VR headsets employ an optical lens that magnifies the display, making pixels that much more discernible. They also require two separate images to create the illusion of depth, fuzzing up the resulting image even more.

"So having a high resolution display means the difference between the individual pixels goes away," says Blau. "And all of a sudden you start to see a smoother virtual world … It gives you that feeling of suspension of disbelief."

While that applies to everything from smartphone-based headsets like Google Cardboard to fully integrated devices like Oculus Rift and HTC Vive, it's the standalone head-mounted displays that are more likely to benefit. They tend to be wired, meaning battery life isn't an issue, and Blau notes they can take advantage of the powerful processors of a tethered computer. Smartphones will have made plenty of advances by the time the new Sharp display reaches mass production next year, but being able to sustain a high-quality 4K VR experience for any amount of time—if it all—isn't likely to be one of them.

So while you're right not to care much about a 5.5-inch smartphone display stuffed with more pixels than you could ever hope to see, if you care at all about virtual reality your excitement is justified. If VR is to find mass appeal, it must feel more real than virtual. Sharp's 4K mighty mite, and those that will surely follow, will be what finally makes the goofy headsets of the future more like looking through a window than a screen door.