I can understand the drive to replace the 3.5 mm jack with something (genuinely) better and more efficient BUT…
1. “Thinner” is irrelevant for smartphones. Check out this from David Pogue:
The cylinder that accommodates your headphone jack is now among the thickest components of your phone! It’s thicker than the screen guts, the circuit board, or the battery.
The headphone jack is what’s preventing phones from getting any thinner. It’s the limiting factor.
They don’t need to be thinner! That is an outmoded design concept. Existing battery technology is not particularly new either, we have had lithium ion cells for a long time and so we have had pretty much the same energy density in our batteries. Making thinner phones means less volume available for batteries so less total energy available for use. Most smartphones cannot survive longer than a day with moderate use. None can survive longer than several hours with intensive use. They are first and foremost meant to be mobile devices so having to plug them into charge (at the wall or with a charging device) defeats their primary purpose.
Phones should certainly not get any thinner as that would not solve any problems they face at present. It would not improve their ergonomics; it might in fact make their ergonomics worse. Phones would benefit from getting a bit thicker and having larger batteries.
2. Secondly, with the abolition of the 3.5 mm jack we will face a choice of multiple connections to replace it. The good thing about the 3.5 mm jack was that it was essentially the standard. Replacing it with a choice of many is not good because we will need to use one type of connection for one device and another for a different device, so in addtion to headphones a range of adapters will be required. That’s a more wasteful approach to resources in comparison to having a single standard. Choice is not always good.
Now consider a usage scenario offered by using the new jacks e.g. the Lightning connector for the iPhone. They enable the phone to supply power to headphones. But that’s exactly what is not needed – more power going out of the phone! We need more energy in the phone; not more going out. Also with the 3.5 mm jack it is possible to listen through headphones and charge your phone. Without it you will have to make a choice: charge phone or listen on headphones. Unless of course you buy another adapter!
What do you think: are you happy to see the back of the 3.5 mm jack, will you miss it, or were you hoping for something better to come out of its demise than has done?