I like aux because it's easy. It just works.
> It has NFC for pairing with wireless headphones, but it also has a headphone jack so you can choose. Shock of horrors
Although the best one I own is a Stax which needs an entire speaker amp.
(My old galaxy s2 had microsd, replaceable battery, grippy exterior,and of course 3.5 mm jack while being smaller in every dimension so I am skeptical as to some of the arguments other than "apple did it so entire industry will copy it")
As indicated above - I'm not am audiophile but I enjoy listening to music, and miss the easy convenience of 3.5mm jack on my phone along with everything else. A headphone amp would completely counter act the convenience and practicality.
I still have them both with me and in active use - mostly as remote controls, kids games, etc.
Perhaps more pertinently, my daily driver is a Galaxy Note 8, which also has a 3.5mm jack and MicroSD card. There's really nothing that my 4-generations newer, work-mandated iPhone has, in terms of functionality and definitely battery life, that Note 8 does not. iPhones are about sexy impracticality, and that's clearly where market has gone (Unlike S2 & S5, Note 8 also cannot be held without a case) - I'm just a old grouch who misses the olden days :).
Labeling those who vehemently miss 3.5mm as audiophiles is a straw man or phenomenal proportions.