You can record videos for later playback on the AVP, in case you care. There's also UWB and magsafe on the vanilla 16. And the dynamic island and the camera control button. But it's mostly little things, which many people probably don't care about.
Currently, this is roughly true. But there's a decent chance it will have a killer app within the next ~5 years, and then adoption will grow quickly. At that point, it would be nice to have a small library of videos/photos that were taken with the AVP in mind.
Regardless of the AVP's success, there will probably be some AR/VR device that becomes popular, and can read this format in the future.
VR is not usable if it's not ultralight on account of the physical pain the weight of the headset causes. Of course the AVP is the worst for this as it's made of metal and glass.
Try it in the store. If it's anything like my 12 mini, the wide angle lens creates too much distortion to use for portraits. Occasionally I use it for landscape photos, but I wouldn't miss it much.
it's probably better to get iPhone 15 Pro even if second hand but good condition. On swappa you can get it for $550 and iPhone 15 Pro still support apple intelligence.
I don't see much in favor of the vanilla iPhone 16. Is the extra camera lens useful for anything beyond portrait mode?