I would say the usage of an ipad is different than the usage of an iphone. I rarely touch the power button of my iphone. So doing so would now be an extra step.
But I assume you hold your iPhone when you use it. Even if not, an iPhone is predominantly a touch operated device so you already have fingers it. Sure briefly moving one of them a fraction of an inch is a step, but so much so it would be some major problem?
But the thing that has been repeated ad nauseam is that no one wants to force you to Touch ID. Nobody wants you to have to make that extra stop. Nobody has called for the removal of Face ID. It is only people like you who want to tell those of use for whom that is not a good technology that we should be going out of our way and making the extra steps instead.
Power button is covered by a case, in many cases. Touch id under power button would not be viable on an iphone.
As shocking as it may sound, they can now make cases where the power button is not covered! Just like how some iPhone and iPad cases has gaps for the buttons. Just like how all iPhone cases have a gap for the mute toggle. It is amazing what science can do now.
And not only that, because of the redesigned camera area and button positions, existing iPhone case are not compatible with the iPhone 13 range . Anyone buying a new iPhone would need a new case designed specifically for it, so had Apple included TouchID on the power button it would not have caused any problems to anyone.
Case manufacturers had to redesign all their cases anyway.
Consumers buying thew phone have had to buy new cases anyway.
You would not have been required to make any extra steps.
As much as this issues is subjective, as much as Apple could raise technological argument, it is a matter of objective fact that there is nothing about incompatible cases which make Touch ID unviable.
What is also an objective fact is that Apple have lost a sale from me, going by this thread from others, and are unlikely to see one in the future based on their current requirements. As I said earlier in the thread, the best technology is the one which best provides for its purpose, and Face ID does not best serve me. Maybe Apple do not care about my custom anyway.
It is just a great shame there are only two realistic smartphone options, because I truly dislike Android, the interface, and apps. The effort it took just to add a cardDav server on that platform was excruciating. So it means being stuck with the unusability of Apple hardware just because of the usability of iOs. Something bizarrely cheered on by fans who oppose them making things more difficult for other people to use, even when it would have no effect on them.