That's what everybody else uses. If you want to write edgy, hip and modern documentation you need to use words that other people don't. "Touch" implies a friendly, approachable and non-threatening user interface. It lets your boss know that you're all-in with this edgy new Unix UI stuff.

tl;dr: It's marketing bullshit.

The UI on the 3B1 was definitely nothing to write home about . . .