What a ridiculous question. He's 3, buy him the cheapest watch that tells time. Are you that ill equipped to make a decision on the benefits of a watch to the needs of a 3yr old. It's any wonder he's made it to 3 if that's the case. What information were you expecting to get?
Suggestions from people about what could possibly help him learn how to tell the time? Not exactly a serious thread as well since I played along with the Apple/Rolex thing but I don't see the harm in asking. I was hardly asking for a £500 smart watch for him.
Did your elders not teach you that if you've not got something useful to say you should keep quiet?