Are smartwatch apps squeezed-down versions of smartphone apps, or more wrist-worn remote controls for the software running on the device in your pocket? Marco Arment thinks it’s the latter.

Arment, who first came to prominence with read-it-later app Instapaper on iOS, is now focusing on his podcasts app Overcast, including its Apple Watch app. Which, just a few weeks after Apple’s smartwatch went on sale, has already been redesigned.

“I originally designed the Apple Watch app for my podcast player, Overcast, with a scaled-down version of the iPhone app’s structure. This seemed like a sensible adaptation of my iOS app to the Apple Watch. In practice, it sucked,” wrote Arment in a blog post outlining the lessons he’s learned so far.

Why did Overcast’s app suck? Arment cites the load times of Apple’s WatchKit software as one reason, describing it as “frustratingly unreliable” when communicating with the parent iPhone over Bluetooth.

“Apps or glances will sometimes just spin forever instead of loading, and even when everything’s working perfectly, apps still take so long to load and navigate that the watch’s screen often turns off before you’ve accomplished anything,” he wrote.

The redesigned version of Overcast on Apple Watch focuses on its “now playing” screen, rather than mirroring the three-level navigation of its iOS version, with Arment advising developers not to underestimate the importance of the device’s glances interface, which people access by swiping up on its main watch face screen.

“Trying to match the structure of the iOS app was a mistake. For most types of apps, the Apple Watch today is best thought of not as a platform to port your app to, but a simple remote control or viewport into your iPhone app,” wrote Arment, whose blog has become an influential voice in the app development scene.

“My initial app was easier to conceptualize and learn, and it closely matched the iOS app. But it just wasn’t very good in practice, and wasn’t usually better than taking out my phone ... It’s unwise and futile to try to shove iPhone interfaces and paradigms into the Apple Watch. Instead, design for what the Watch really is.”

That’s a principle that applies to all smartwatches – Android Wear and Pebble models included. “The Watch seems to fit on a continuum somewhere between the iPhone and, say, a Bluetooth headset — part peripheral, part computer — and it will likely stay there,” he added.

“Not every computing device should or will become a general-purpose platform.”