If wearable technology is to make a breakthrough soon that might be because it will be completely unobtrusive or even invisible.
"As the smart wearables market continues to grow and evolve," said analyst Gartner, "by 2017, 30 per cent of smart wearables will be completely unobtrusive to the eye".
Will they be pervasive? Well, by 2018, more than 25 million head-mounted displays (HMDs) will have been sold as immersive devices and virtual worlds will have transitioned from the fringe to the mainstream, Gartner said.
And interest in HMD devices, which power virtual reality systems and augmented reality and other smartglass applications will be so popular that by 2018, said Gartner, the technology behind them will be used, "in a variety of consumer and business scenarios".
One catch is a lack of software
However, one of the biggest barriers that might blight the uptake of wearables will be the lack of mature software, Gartner reckoned, and another will be concerns over privacy.
Also, said Gartner, HMD technology, "is expected to have a different and slower trajectory over the next few years compared with the fast adoption that was seen with the introduction of smartphones". But the analyst predicts this take-up is certain to accelerate when users increasingly experience "immersive worlds offered by well-made VR and AR apps through their headsets".
By 2016, biometric sensors will be featured in 40 per cent of smartphones shipped to end users. "Fingerprint scanning will be the primary biometric feature introduced by most vendors," Gartner said, because of its intuitive and unobtrusive use. Other biometrics such as facial, iris, voice, and "palm vein authentication" will also emerge but will remain relatively niche, it said.
"Wearables will also feature biometrics as coupling devices to smartphones," said Gartner, "but will mostly obtain the biometric information to be passed onto the smartphone where the intelligence and authentication take place".
Impact on PCs
The growth in wearables and smartphones will have implications for the PC world, said Gartner. It predicts that by 2017, "one-third of consumers in emerging markets will have never owned a Windows device".
In emerging regions, PC penetration is low and some consumers have never owned or used a PC - and they never will, the analyst notes.
Mikako Kitagawa, principal research analyst at Gartner, said in emerging markets, consumers' first web-connected device is often a basic phone with some browser capability, and they will upgrade to a phablet or tablet and not a PC.
According to Annette Zimmerrmann, a research director at Gartner, while wearable technology is going to be a big success it may not be a success generated in the US or Europe.
"Yes, people [in the US and Europe] are talking about it," she told ZDNet, "but if you go to China, Japan, and especially the Far East, you will see them actually developing the technology and the products and doing it very quickly."