I'm thinking about it because we'd like to build our deck out of wood: the decking, as well as the structural support. I'm not a fan of plastic composites and I don't think we can afford aluminum and I like wood. So wood it will be.
Wood weathers when exposed to UV light. It turns grey without treatment. All woods do this. Some will also bend and twist and shrink. But if you choose the right kind of wood, it will hold its form for hundreds of years and only the color will change, even if you do nothing to do it.
During the time that the wood is changing color - going grey - it can look quite uneven. Some people try to retard the process by painting or sealing the wood.
But the process can be quite beautiful.
I'd love to see more weathered wood in the States. Seems like most of it is reserved for shingled houses by the beach.