Well it's cargo cult UI design
Mobile phones now have converged on touch screen, so some people, who don't understand the problem now believe that touch screens are somehow suitable for all applications.
If you look at car radios you will find that they are all designed to be used without looking at them. The left knob was volume and power, the right one was tuning. In more modern ones you choose the station by pushing buttons below the display. You can easily distinguish them. That's decent user interface design. That's also why your f an j keys have a little hump, or why your desk phone has just such a hump on the 5 key.
Biting the hand that feeds IT
