HN is usually pretty utilitarian, I'm sure there are a lot of people on here that admire Mark Zuckerburgs "style" and seek to emulate it by not caring at all about how they dress and simply optimizing for clothes that will last the longest.
But there are also people out there who are influenced by wanting to look in a way they perceive as nice or cool and still have a satisfying life. I appreciate the tech culture that helped eliminate the suit but mostly because I like the way I dress and it's a form of expression for me. Plus it's nice regularly getting comments for putting in a little effort without having to resort to business casual. I know specifically my younger cousins admire that I can do a programming job and still wear (and are able to afford) clothes they'd want to wear.
Perhaps if the USPS trucks weren't the ugliest design that satisfied specs and instead seemed like some cutting edge vehicle there might be people out there who are growing up that would actually find it kind of fun or cool to drive around a USPS truck. It might be nice for it to be a job people want to do versus it being a secure job where you're the joke for driving around the ugliest vehicle on the road while dodging people's dogs.
As a simple example that well design can still be top quality, look at any of the trains on the Tokyo subway and train systems versus any train system in the US. They're far better functionally than any of the trains in New York or Chicago and look alot better inside and out as well. Maybe it looking impressive and not a tin can on wheels contributes to the increase in ridership for all groups of people, maybe that makes the job to be a conductor highly competitive to the point of it being a college degree worthy job. There are other things the train system does well but you still want to not hate riding on the vehicle.
An even simpler to understand example is the early days of android vs iPhone. Android was simply uglier but wasn't that different functionally. It was just extremely ugly to the point of people not wanting to buy it if they could afford to otherwise, so much so that Google invested a ton of money in creating Material Design