"Clothes are sometimes wet and dirty and odorous, so a bag comes in handy."
When my clothes are wet after hiking in the rain, I like to bag them up and throw them in the sleeping bag with me to keep them warm for the next morning. I'm also a creature of habit. I like knowing that I can reach blindly in the dark into my ruck and will know exactly where any piece of gear is. It's also nice knowing that if I pull my rain shell out of my pack, I don't have to worry about my glove liners, etc accidentally coming out with it and leaving them on the trail. This is an area where the .25oz weight penalty is worth the convenience.
If anal explosive hiking is your style then HYOH I suppose.

