MoguriHi! Great question! Confirmed with Kelty that the benefit of nylon over a cloth (like cotton) would be weight, compressibility and general safety as a heavier cloth like cotton will hold moisture, take a long time to dry and can cause hypothermia in cold/wet weather.
And yes, this is machine washable, though there are some suggested parameters to extend the life of the bag:
- Use a front loader washer and dryer (since the top loaders have an agitator)
- Try and use specific detergents for technical product or even eco friendly detergents work as well
- If you have them, using loft balls in the dryer with the bag will help keep the loft