AOD allows me discreetly check the time. Sometimes my boss will come in around 11:30. I leave at noon for lunch. When he's talking endlessly about nothing, I can just glance and see the time. Same goes for boring meetings. It's impolite to be looking at your watch mid convo, or checking your phone, or turning completely around to look at the clock. AOD makes it easy.
Also, when my phone is on silent, I can see when an email or text comes in. If I'm waiting on something in particular, I can quickly put in my pin to see if it's what I need. For me, AOD just works. It's worth a minor hit to my battery life. And I only have it on 9-4 for work.