I've switched from mostly synthetics to merino wool for general purpose use. Technically, I still think synthetics are better, so if I was backpacking long distances, synthetics would probably be my first choice. They are lighter, dry faster, non-allergenic, and feel better for most people. But the one reason I switched has nothing to do with survival or performance. Wool just doesn't stink as much when you can't wash it. This doesn't seem very important until you have to smell yourself after a few days of not showering. So for traveling, desert camping, or anywhere else you might not be able to wash regularly, that's a pretty big plus. I've heard some of the newer synthetics are better in this regard, but the wool clothing I have beats all the synthetics I've used.

Also, I have been careless and dumb at times, and have had nylon burn my skin. It is not a fun experience, because the natural reaction is to pick it up or brush it off, which only results in two burns instead of one. Luckily it was only dumb enough to teach me a lesson, while not being stupid enough to cause serious injury. It doesn't stop me from wearing synthetic clothing, just taught me to be a lot more careful around hot objects with it. So something as simple as putting on tire chains near a hot exhaust, or having to reach into an engine compartment with a hot manifold, or even cooking around a liquid fuel stove, causes me to stop and sometimes change clothes just to be safe.