Honestly, your argument might hold more water if touch input was the only way to interact with the SB. You never have to touch the screen; with a finger or the pen. It's about having a choice. Trackpad, keyboard, and mouse input are readily available on the SB. For those who want it, touch input is available as well.Totally agree. I can't stand even seeing dust and other smudges that somehow find their way onto my rMBP screen. Frankly, I dislike having to clean my iPad Air screen after my kids get their not-quite-clean hands on it.
And I'll state what I have over and again, that touch input on a vertical screen when your hands are naturally doing input on a keyboard in the horizontal plane, makes ZERO sense and is just not comfortable or manageable for anything other than quick pointing or cursor moving - things that you can do faster and more ergonomically by using a trackpad. I get that trackpads and Windows hardware have been anything but smooth or useful, which is likely part of the reason why MS moved on to screen input, and because they needed something to show they were following the trend of touchscreen devices.