Do you make a lot of phone calls to New Zealand? If so, you might really appreciate a digital watch with separate displays for two different time zones. But if you can add and subtract, you might find that second time zone display a liability.
My watch has displays for: time, data base, alarms, stop watch, countdown timer, and a second time zone. I use the first five displays a lot. But I think the real point of the second time display is to wreak havoc. It takes a lot of button presses to get to it, and sooner or later it will simply show a DIfferent TIme THat IS WRong, so it would be best if I could never see it; but that second time display insists on being visible sometimes, and it usually IS wrong, and it confuses me.