Yes, as you say, by moving the power draw for the DAC to another device, which must be charged separately. This isn't a real gain in battery life in any way.
These people are a pox on public transport.
I also use the phone's internal speakers for playing the notification sound. (And, technically, ringing.) I sure hope that's not going away.
Quite frequently found at highway truck stops, though almost certainly other electronics stores as well.
Wireless is convenient.
Wired is reliable.
YMMV.
Bluetooth's more reliable than USB in a car anyway.
Maybe I'm in the minority but I could never imagine not having music pumping in my ears.
I dont want to charger yet another device in my daily routine. I won't, actually, and will steer away from any phone that requires active headphones to work.
I'm not saying I agree with getting rid of the headphone jack. The amount of utility it provides is pretty high relative to the volume it takes up.
Oh and it felt too damn thin as it is I was constantly wary I would accidentally bend it or scratch the metal casing so i got a rubberised cover. Now it feels a lot better to hold.
That said I've been told that the 3.5mm jack takes up a surprising amount of internal space, and that between freeing up that space and a few other tweaks, getting rid of the jack substantially boosts battery life. Still, I think it's not a great trade-off, now you have to babysit a new battery in your headphones, which probably won't last a full day of use.
On a personal note, anticipated lack of a standard headphone jack is one of the reasons I upgraded to a 6S recently, this way I'll have the best 3.5-mm phone Apple made for a while. If I do have to upgrade later on, I'll be strongly tempted to get an SE instead of a higher end phone, as long as it has a 3.5mm jack.