The only time I use my phone for music is sitting at work for 8 hours.
So the only way I can listen to music is if I let the battery run down while I'm doing it? Unless I pay a fortune for wireless headphones I don't want, only for them to run down too?
I assume some hideous frankenconnector with power and headphones will become available for "a price" but still more money for bespoke crap.
I can imagine the future:
"The amazing iPhone 8 is by far the lightest and thinnest and most beautiful iPhone we've ever made. Just plug the battery into the lightning port..."
The really sad thing is that it won't harm sales, thus encouraging everyone to do it.