[Tycho]

Well I suppose he could just mean he has some principles in mind about what a device should feel like to own. For instance the iPod, it was such a leap in usefulness of pocket music players, and this was reflected in not just the technology (1000 mp3s) but also the UI and the physical controls and the build quality and the stylishness. I say stylishness because I think that kind of is part of 'usefulness'... it looked cool to be seen with an iPod, esp. with the white headphones.

In contrast they could have just been like 'oh, great, we have a harddrive that can hold 1000 songs and still fit in your pocket easily!' and put out something that looked and handled like a brick.

But going back to what he wrote, he mentioned interior design, so he was probabaly thinking about architecture. You could have a boring building and make it look nice inside, but isn't it so much better when the architecture itself is amazing and then everything else just builds on that or compliments that.