Not having physical buttons is a detriment for doing simple tasks that you should be able to do blind (skip track, volume, play/pause, etc).
For me to change the song on a keypad, I just reach down and push one button. For me to change the song on a touchscreen, I have to pull the phone out of my pocket, press unlock, slide my finger across the screen then look at the screen to make sure I don't hit any other buttons while I press skip.