This may be compounded by the fact that the watch needs its own special charging cable, my main pain point is that I always forget to pack the watch charger when I travel so my watch always dies if I'm going for a night.
The tradeoffs are that the screen is "e-paper" without touch functionality. Personally I think it's the right choice: always-on tech and having tactile controls vs a clumsy touch-screen (due to small size).
The watch itself is pretty small so there's room to increase battery life by making it bigger.
All the other stuff these things do use too much power for to get that battery life from just switching to a even a (not physically plausible) 100% efficient photovoltaic e-ink screen.
It could be a fitness tracker like the Fitbit Zip (advertised at 4-6 months), or a plain watch like the Casio F-91W (when I had those as a kid, the battery outlasted the straps), but it can’t be a smart watch.
All of this is moot anyway, it can get 8 hours of sleep tracking in 8 minutes, or fast charge in 45 minutes to 80% - these are far better metrics than if they managed to get it to last 2-3 days.
> Get up to 80 hours of battery life in GPS mode[1], up to 300 hours in max battery mode[1] and up to 65 days in smartwatch mode with solar charging[2].