The supports are good for making pretty screenshots but they're nowhere near practical.
They cost 8 metal bars and have a radius of 13.
Stone supports cost 1 bar, 30 stones and they have a radius of 11.
Purely a cosmetic addition I guess.
It would be nice to see them buffed to 21 tiles since they're fully made out of metal and have 8x's the cost. I would assume a completely metal support is stronger than the stone pillar so shouldn't it be able to support more tiles/weight?