The dirty secret of the electronics industry is that the reason for moving to sensor buttons is cost.
When first capacitive touch devices appeared around 2005-2006, everybody immediately noticed that you only need a single digitizer for the whole front panel of the device, or dirt cheap cap sens circuits for point sensors.
For as long as the sensor is just a piece of polyimide pcb you can glue to anything, but a metal surface, things get really cheap without mechanical buttons, holes in the case to cut, and PCB to hold the buttons.
When first capacitive touch devices appeared around 2005-2006, everybody immediately noticed that you only need a single digitizer for the whole front panel of the device, or dirt cheap cap sens circuits for point sensors.
For as long as the sensor is just a piece of polyimide pcb you can glue to anything, but a metal surface, things get really cheap without mechanical buttons, holes in the case to cut, and PCB to hold the buttons.