The real answer is that I use it when bushwalking – I also have a “proper” one for things that need more accuracy, but this works and is always handy. More recently, I figured I might as well have some fun with it. So now my answer (to adults) is “I’m an atheist, so this is my moral compass.”
People also wonder why I wear my watch on my right wrist, even though I’m right-handed (for writing). I actually throw left-handed and tend to catch with my right hand – but that’s a sideline. Here’s the truth: the origin of the choice-of-wrist is decades old, and was part of an experiment that stuck. You’ve probably seen or read detective stories, where the brilliant deduction is made that because a victim or suspect wears the watch on the right wrist, and “therefore they must’ve been left handed”? Being young and already inquisitive, I thought I’d just test that and of course it’s complete nonsense. But I kinda got used to wearing the watch on the right wrist, and it’s a neat reminder that while Occam’s Razor is a good guide, drawing far reaching conclusions on seemingly obvious little things can easily (and thus quite often) yield invalid results!