What if Apple’s so-called iWatch isn’t a watch at all?

March 25, 2014, 5:28 PM UTC

Android Wear

FORTUNE — Google (GOOG) may have done Apple (AAPL) a favor when it posted two promotional videos (attached below) for what it’s calling Android Wear: A new extension to the Android operating system released last week to developers.

The videos are very good — both for their production values and for showing what can be done on a wrist-based touchscreen connected wirelessly to a smartphone that’s connected to the Internet.

But they also suggest — at least to Benedict Evans — that what Google has planned for the wrist may be very different from what Apple has up its sleeve.

“The Wear concept,” Andreessen Horowitz’s newest partner writes on his personal blog, “is that smart watches are remote touch displays for an Android smartphone. Now contrast this with the rumours of a new Apple ‘Healthbook’ app.”

“Healthbook” leak. Source: 9to5Mac

Leaked Healthbook screenshots show a display of “cards” offering a range of health-related data: Hydration, blood pressure, blood sugar, heart rate, respitory rate, oxygen saturation, etc.

It’s hard to imagine a device that can measure all those things fitting into something stylish enough to meet Jony Ives’ exacting taste in watches. But if Evans is right, it wouldn’t have to.

“Suppose for the sake of argument,” he writes, “that Apple does indeed plan a health app that’s card-based, somewhat like Passbook. What would happen when you buy and turn on a blood pressure monitor that is certified for ‘Healthbook’?

“Well, one would expect that Apple would use the Bluetooth LE auto discovery that’s already in iOS7 to detect it automatically and tell you. And then, suppose it offers to install the Healthbook card to manage it… Suppose it does the same for any sensor you might buy? Then Apple has created a zero-setup platform for personal health devices. No apps, no native code, no app store, no configuration at all.

“This would be one answer to why Apple’s recent hires of ‘wearables experts’ sound a bit like a team for a hospital device rather than a watch, measuring various quite technical things — because Apple plans to enable such devices, not try to pack every single one into its own device. That is, the straightforward sensors should live in the phone (like the pedometer that’s already in the iPhone 5S) and the complex and demanding ones should be enabled by an Apple platform, not become part of an Apple device.”

The issue for Apple and Google, Evans writes, is where the code lives. Both companies seem to be saying that the “smart” part of wearable devices should be concentrated in the smartphone or tablet — something that’s easy to update and gets replaced every couple of years.

“Everything else,” Evans concludes, “should be a dumb sensor or dumb glass or both.”

LINK: Cards, code and wearables

Tip of the hat to 9to5Mac’s Mark Gurman, who broke the Healthbook story.

Below: Google’s Android Wear videos.