Same how sex sells for humans, design and looks sell the same way for objects, from phones, to PCs, cars, washing machines, etc.

Consumers don't understand tech specs, so if you show them something that triggers their lizard brains because it genuinely looks really good, appealing, futuristic, trustworthy, etc, then they'll buy it for that.

The issue is that most designers are snake oil salesmen, so from the perspective of management and C-suite who approves designs, you can't objectively verify the claims and buzzwords of the design team. See the pepsi logo redesign fuckup.