I found an old post of mine on Usenet, which I'm going to quote in full here.
I'm blind, and I find it a bit difficult to actually use a smartphone for the purpose of making and taking calls, mostly due to the lack of physical buttons. Conventional handsets are quite easy for a blind person to use. The keypad is familiar. The ten number keys, *, and # are all arranged in a conventional layout. To take a call, just lift it from its cradle or hit another physical button. I learned to use and dial a phone when I was about two. I also learned to dial rotary phones. There weren't too many of those left while I was growing up, but there were a few. They're not as convenient, because you have to count holes. In any case, the standard touch-tone phone facilitated quick and easy calling. It's a great example of universal design. Compare this to a touch screen smart phone. If it has screen reading software, I can dial it, but it's clunky. I don't remember which is faster: rotary phone dialing or dialing on a touch screen. The touch screen may win, but not by much, and yet, it is a regression when compared to the physical keypad.
The problem with touch screen devices is that they aren't very tactile at all. I'd think that something with "touch" in its name should be a harmonious tactile experience, but in this case, all I'm doing is poking or sliding my fingers on a blank, featureless screen. It has no landmarks. My fingers weren't just meant for poking and swiping; they were meant to convey information to me by actually feeling things. Touch screens deprive me of much-needed sensory input. Unfortunately, we live in the age of the image, and the other senses often get short shrift.
The post ends here. Apparently I forgot to mention another feature of old-school physical keypads: the tactile landmark. The overwhelming majority of landline phones that I've used in the US had a bump on the 5.