A bit like the blasted music (which they often walk away from and leave playing outside), I think they don't know why they do some things, only that it's some kind of indicator of money or status. Anyone who's anyone has a chiminea in their garden. They have it belching flame then sit at the opposite side of the yard, ie not getting any benefit from the warmth, so the smoke doesn't go in the house.
They've also bizarrely covered a small part of their garden with pebbles and dozens of mini gold and silver Buddhas, about 20 of which are on little shelves on their garden fence. Plus a few plaques with 'live laugh love' written on them.