I'm wondering what the deal is with these. This isn't a question of how to set it up, but rather why are they so prevalent? My older G-shock has a tide chart with a moon phase indicator so I understand it in the context of predicting tides. My new Mudman only has the moon phase and moon age. What's the purpose of knowing just that? I feel like I'm missing something since more and more G-shocks have these indicators.