I'm not sure it's always just about utility vs. signalling. I have no care for social signalling at all, but if I had money to throw away I would probably buy some things which you classify as signalling devices. For sure, though, I certainly wouldn't buy a blinged out gold Rolex (hideous) but rather something like a Speedmaster (on which I'd probably put a NATO or a velcro strap), and certainly not a sports car you can drive on public roads. Sure, both of these machines don't have that much practical utility, but they are engineering works of art. Just as some people collect art to show off their money, or store capital, some collect it because they appreciate good taste and amazing craftsmanship. It's still irrational but I wouldn't put it in the same bag as signalling.