I guess it depends on the type of headphone you are using. I could see your problem with those short wire earplugs with one wire to each ear where the wires are hanging between ears and phone. Not so much with the longer ones that only go to one ear and have generally thicker wires like an over-ear headset.
Yeah, but you can always charge while you are sleeping or otherwise not using it but if you want to listen to stuff in an environment that requires headphones you have no choice but to have it plugged in at that time. Can't exactly pre-play your music or audio book into your headphones at night.
If you want to use it for other things at the same time, then yes, it can't lay flat. I really don't see how the concept is so difficult to understand.