Don't get me wrong, nice things are nice. Go figure. But I work in a mixed city with people from much higher and much lower than me on the economic latter. In my experience, owning a lot of nice things means that you're going to have a harder time befriending people who are significantly lower on the income latter. I don't expect this to be a problem for everyone, but for me and I suspect people like me, it's difficult because I just like going out and being social in meatspace. There's plenty I could do to overcome that when I meet new people, but I don't want to have to overcome walking in and looking like the rich guy. And I don't want to have to think about going to a concert at a bar in a poor neighborhood because I drove a nice car.
Things like saving for my children, as the article discusses, make sense because they tie in with long term happiness imo. If I ever do have children it's not hard for me to imagine wanting to give them as much support as I can to ensure they succeed. I wouldn't want to see them struggle because of resources. But luxury goods don't affect me longterm happiness in the same way and often they feel to me as having a social opportunity cost. The difference in price between what I drive and a nice car could fund a lot of bar nights, concerts, parties at people's houses, etc. And that's just not a cost that's worth it from my perspective.