Earlier quoted context omitted.
> The burning of significant amount of wealth is a costly signal of commitment to the receiver. So why not buy something practical and expensive? Like a house or a car?
Because houses and cars are useful, the GP pointed out that being uselessness is the entire point >the high cost and useless-ness of the gift are a feature not a bug The other thing is the marketing says diamonds are "forever," presumably like your love, but houses and cars require expensive maintenance and are easily damaged. Not good if you're buying something symbolic. Not that I personally agree, far from it, we…
Definitely some symbolism there. Relationships (romantic and otherwise) are indeed more like houses and cars - innately valuable, easily damaged, and requiring regular maintenance - than diamonds.