No. The UI designer does not choose functionality on their own. They need intimate knowledge of how the car and driver work together, and then must simplify to

No. The UI designer does not choose functionality on their own. They need intimate knowledge of how the car and driver work together, and then must simplify to the bare necessities. The better they are at the job, the better they know about both. And same applies to the developer and even the driver. The best drivers are deeply involved with every aspect of their cars. And in the end, nothing is redundant. And no, MS Paint and Photoshop are not the same program with one just having more options. Photoshop is a beast, and it's UI has improved over the years -- to match that functionality. The UI is different because Schumacher is driving an F1 car. > additional options with non-obvious discovery This is bad design. iTunes and Apple Music are horrible also. Not everyone at Apple gets it. But everything that made Apple successful was about getting it. Steve Jobs got it. > designer happiness There is only designer happiness among those who don't get it. There is no designer-developer distinction to the user. Ultimately all there is is user happiness.