The concept of conspicuous consumption has really never occurred to you? Why do you think people aspire to own a Ferrari or a Rolls Royce? Because they are going to get a practical benefit from having a high-power car on their commute down the M5 to work, or whilst popping out to get some milk? People buy these things because it says something about their wealth, status and perceived power: penis-extensions of the most basic, primal, show-off-and-display kind. It's the human equivalent of a peacock showing his feathers.
And what about the sad middle-management goons from Slough that go out to their local West-End night-spot every Saturday, sit in a private paid-for booth and order expensive brand vodkas? Are they drink connoisseurs? Vodka experts? Or perhaps it's the fact they want to be seen dressed in certain branded-clothing, drinking certain expensively-priced drinks. Perhaps they think it will make them seem more wealthy - and hence more attractive - to members of the opposite sex.
Conspicuous consumption is one of the driving engines of our consumerist society. "Keeping up with the Joneses".
Or some people buy these types of cars because they are a petrolhead?