The corollary is that you have to worry about the DAC in the phone if you have an analog jack, and they're not good. So with digital only, you have the option of buying a good off board DAC (if you care), or otherwise selecting digital headphones at a price point you like.
All that said, I'm struggling to see the good side of Apple's decision to remove the 3.5mm jack. It'll make the phone worse in daily use for me - I won't be able to sit at my desk all day and charge my phone while listening to my existing, good headphones.
The DAC in the iPhone is as good as any external DAC you can buy, when it comes to human perceivable sound quality. Any other claims are audiophile BS and placebo.
There are valid product reasons for moving away from the 3.5mm jack though, like adding a power line that allows you to make active noise-canceling headphones that don't require their own battery, or outputting to more than two (stereo) speakers over a single cable.
There are also ways to do Active Noise Cancelling without an external battery and without a new cable. I had an old Sony laptop that did ANR with software on the laptop and mics on the earpieces wired back into the laptop. Also the connector was backward compatible with a standard 3.5mm. They just used a 3.5mm connector with extra conductors on it like this one:
https://www.amazon.com/Connectronics-TRRS-Conductor-Metal-Au...
I had one of those tiny Sony Vaio's that did the same - great idea and tech but did you ever use it in comparison to the state of the art from Bose etc? It was night and day - the Sony was barely better than normal ear buds on an aeroplane...
I agree, I remember it being very poor compared to my Bose aviation headset. Still was a cool proof of concept. I imagine with the right software/hardware it could work just as well as external ANR
Here's the thing though - you have to have a DAC in the phone anyway because the phone needs to have a speaker built in. Now, it might be nice for some people to be able to get an external DAC in addition, but that should already be possible with something like USB OTG.
Nice external DACs connected to phones is nothing new - USB OTG has been around forever, and even back in the "iPod Connector" days digital IO pins were available. Lightning does not provide anything new in this regard - and certainly nothing more than Lightning + 3.5mm ever did.
The problem with external DACs is that they don't easily fit in your pocket and cost a pretty penny. Cheap headphones will get even worse and good ones will get more expensive for including a good DAC.
There are no winners in this game except for Apple, which can push more licenses and proprietary accessories.
> The corollary is that you have to worry about the DAC in the phone if you have an analog jack, and they're not good. So with digital only, you have the option of buying a good off board DAC (if you care), or otherwise selecting digital headphones at a price point you like.
You could already connect an off-board DAC to the iPhone pre-iPhone 7
my wife has a dock that does this with her iphone SE. it doesn't use the 3.5mm jack, just lightning. So I'm speculating it's not a limitation of the lightning connector per se, but that of the dongle.
All that said, I'm struggling to see the good side of Apple's decision to remove the 3.5mm jack. It'll make the phone worse in daily use for me - I won't be able to sit at my desk all day and charge my phone while listening to my existing, good headphones.