Gosh Tine, how élitist of you
There is a point to it. It builds brand awareness while marketing to
future potential Rolls-Royce buyers.
You could just as easily ask why does Patek Philippe or Mauboussin bother to advertise in Tatler or Vanity Fair.
Those magazines are mostly read by people who aspire to live a higher-end lifestyle more than those who actually do.
Luxury brands live or die on their image.
Mercedes and BMW are aspirational brands for the middle classes. But for those who aspire to the highest levels of wealth and culture, brands like Rolls-Royce must carefully control (even contrive) their image so there is no ambivalence about what the brand represents. My point is, Rolls may be targeted at wealthy individuals, but its entire image relies heavily on how it is popularly perceived by the masses - and this is very deliberately cultivated. It's not enough to just create the most luxurious and expensive product ...you must also sell the dream/emotion/fantasy.