Nowadays a few creative people wear a mixture of assorted hats with wich they are judge& jury (judge and jury is an expression, a book, a restaurant and i'm sure a whole bunch of other things) tax avoider, landowner, and boss of the plaines.
Some say a career in the theatre would haven been appropriate for "hats" so we can enjoy and keep an eye on them at the same time, some think the political arena resembles a lot like theatre.
To call somebody a "hat" can imply, that you're impressed by a persons acting skills, or as an offensive remark, it depends on the intonation.
" I know her from somewhere, doesn't she own something? She's a hat. Oh!"
" YOU HAT! Oh, thank you! IT'S AN INSULT! I couldn't hear my hat is blocking my ears."
" Hat? No, thanks i'm good."