They explicitly address this in the article:

"Initially, we experimented by building this as an app on Pebble, since it has a mic and I’m always wearing one. But, I realized quickly that this was suboptimal - it required me to use my other hand to press the button to start recording (lift-to-wake gestures and wake-words are too unreliable). This was tough to use while bicycling or carrying stuff."

This interacts directly with the Pebble App, so I would be shocked if the watches never get an equivalent app.