Power remains the single biggest issue impacting the usefulness of smartwatches. With currently available technology, there’s just no great way to give them the functionality and performance we demand, keep size and weight down to a reasonable figure, and get anywhere near the kind of battery life we’re used to from traditional watches. That said, every new generation tries to strike that balance just a little better than smartwatches before, and thanks to efficient new processors and software optimizations, sometimes we really do get to see meaningful gains.
Then there’s the problem of when to charge these things. They want to monitor our sleep. They want to monitor our workouts. They even want to monitor when we’re just sitting at our desk (if only to tell us we need to get up and start moving). When are you supposed to find time to take your watch off to charge?