The argument at play here seems to be: you can make something that looks like a Braun device if Braun doesn't already have a design-patented device that does the same thing. And you can make a device that does exactly the same thing as a Braun device as long as you don't try to make your device look confusingly similar to Braun's device. What you can't do is make a direct substitute for a design-patented Braun device, and then go out of your way to clone the design so that people have a hard time telling the difference between the two.
Another simple way to look at this (it's incomplete, but might settle the issue for you) is that a lot of people pick their phone based on how it looks.