I have a Pebble (well, Pebble Time now after the replacement) and I've found it has been very beneficial for me in a number of ways. The main benefit I get in the kitchen would be the Timer functionality so I can just set something to cook for 5, 15, or 30 minutes on my watch and it will vibrate my arm when it is done. Easy to access from a glance and I don't have to turn around to the stovetop timer if I am away from standing there.
Also what I like about my Pebble is that it mirrors all notifications on my phone, so if it is a text message, email, phone call, or any app I get a quick buzz. Since it is not specific to apps, I imagine that Joule would work exactly the same way! I'm excited to get notifications that say "Your water is ready" or "Be ready for the best steak of your life." That said, do any of you have a Pebble right now with the Joule app? Does it work as I describe? I don't see why not, but just don't feel comfortable making vast claims without testing it myself.
Also - I know that Ben of ChefSteps has the Apple Watch. I'm just a layman who doesn't have one yet!