I use the dock as a bedside alarm as well. I get annoyed easily by lights on when I'm trying to sleep, but I actually quite like the soft blue glow the clock gives off during the night. Plus, I really like clock function as well. I don't have any other alarm clocks in the room, so sometimes when I wake up in the nigh, it's nice to not have to reach for my phone to see what time it is. And I like seeing the weather first thing in the morning.
But back on topic, I've charged every smartphone I've ever had overnight. Never experienced any sort of 'super fast battery degradation' or anything. Charging overnight is the best time to charge a phone anyway. I don't have time to charge it while at work, so, overnight definitely works best for me (and most people I'm sure).