Just because it's innovative doesn't mean it's non-intuitive or difficult to use.
A few of the other points reinforce exactly that, such as:
#4 Good design makes a product understandable
#10 Good design is as little design as possible
The fact Dieter stripped out the inessential aspects and frivolous features, focused on the intended function and made simple products aesthetically pleasing was innovative at the time. And still would be today for most consumer electronics.
