Yes, I use one all the time. I have a small collection of them, depending on the task.

As for why I use them?

- They are tactile.

- They are forgiving, pushing a button doesn't accidentally swipe to some random app or screen or slide down notifications.

- The physical calculator doesn't interrupt my work with a notification or popup.

I realize it makes me a boomer, but using modern smartphone interfaces, especially post-home button iOS, feels like interacting with a UI sitting on top of a banana peel. Buttons now require more precise and well-timed touches to activate their actions (eg: the buttons on the lock screen). I frequently find myself accidentally swiping between apps or navigating to new views.

I really wish I could go back to the old way of having a singular app be the focus, and having a home button or something I can press to switch between app contexts, without all the easily triggered and hidden gestures.