If you're not interested in giving google/apple the last piece of your daily schedule (exercise/sleep tracking) the only thing a screen that small is good for is saving the 5 seconds it takes to check the phone in your pocket to see who's contacting you, and in exchange for this you need to remember to charge it daily. Unless you get a lot of unwanted contact while not sat at a desk where you can see your phone screen anyway they seem utterly pointless to me.