All possessions are fundamentally irrational. I'm baffled why people would collect vinyl, buy overpriced designer clothing, pay for expensive tickets to sport, buy expensive kitchen implements - and on and on and on.

I like cars. I like driving. There are some cars I'd be happy to own, even if they didn't go. I spend money on buying, maintaining and driving cars because it's something I like doing.

This is no more or less irrational than any number of other discretionary spends. So you shouldn't be baffled anymore.