Earlier quoted context omitted.
I'd also note that despite Jakob Nielsen's prominence nobody designs like he suggests. We should be open to the idea that beauty and delight may be more important than usability or features.
Respectfully, fuck that. Beauty matters the first time you use it, whereas functionality matters every single time. Or, in business terms, beauty has terrible ROI.
It depends. For typical software and websites, beauty matters every single time: when you like something more and more and more every time you use it, to the point of increasing usage, recommending it, spending money and so on; and when you hate something so much that functionality is effectively reduced by avoidance, distraction, fatigue, rage quitting etc.