I think it could also be used as a close-proximity distraction. Say you're between some vehicles or behind a wall and you know some zombies are nearby. Set the alarm a minute or so ahead and chuck it away. The thought is to draw away the nearby zombies so you can get to where you want to go or escape. It would be loud enough to attract zombies nearby, but not loud enough to draw more zombies to your area (like say a gunshot).
It would be great to see a smartwatch instead of the book for things such as your calories, food and all that status stuff.. You press the button, your character moves his arm into view where you can see the watch, then it zooms in on it slightly..
Overall Health & Heart rate
Gets rid of that ugly diagram and adds a uniqueness to your game ( plus since smartwatches have all that junk nowadays anyways wouldn't hurt )
The smartwatch is of course, solar powered and gets its energy from being out in the sun which is indeed a real thing
I like the idea of using it for a quick reference on some basic info i.e heart rate, maybe dehydration state and oxygen level etc (they do that, right?)... but nothing to replace your stat screen like the fallout pip-boy, I honestly like the Journal/Notebook that they are running with now... but still something like this would be good to check without needing to stop, much like the wristwatch in the "Metro" games where it's visible while holding a weapon/item...
So in short, Yes I like it and there is a use for it... but not to replace the current Journal
Given that the day/night/year cycle is going to be SO important, finding an item that can give you an accurate date and time is going to be critical to long term survival. I fucking love this idea. TBH the time and date get me more excited than the map does.
I think I could stand to see a gps feature on the watch if it is a more rare tier 2 version of the watch. Almost all digital watches have a calendar function. GPS is a much more high-end feature, although not unheard of.
I like idea of a watch that only tells time. Maybe a self-winding analogue watch. It could even have a cracked crystal to show that it is a crappy and inferior watch.