My best guess is that the Camera Control button was a late addition that Apple maybe threw in to try to impress all the Europeans who won't see any Apple Intelligence for months, or probably years.
Or just to tie over users in countries that do get all the AI features ASAP, as they'll also have to wait several months before it's all implemented.
Regardless of which region you're in, I think Apple was worried iPhones 16 wouldn't offer enough at launch, that too many would wait it out to iPhones 17, when all the iOS 18 AI stuff is actually out.
I don't know.
It is, however, kind of weird how badly it's implemented as I genuinely think that the concept of a dedicated camera button is a no-brainer on paper.
The fact that it only works to wake up the phone, not launch right into Camera, is really odd.
However, I don't see why this can't be changed in software. And seeing how many complaints it's getting, I'm sure Apple will give users the option to switch between different actions.
But still weird that they thought anyone would like what it does now. Poor choice by Apple.