UX Perception is key
As in all things the truth is very rarely important. The perception something is much more important. In UX design this boils down to what the user feels and thinks about what they are using.
(Talking about the Gamecube controller) the greatest videogame controller ever designed, mainly because it had a really big button on it. - the RexBox blog
Simplicity was created, not by actually removing buttons, but by showing the user a primary button. Subsequently most design focused on that big green button. How we perceive an object, function or service is a lot more important than how that object, function or service actually works. Most companies get this wrong again and again.