It's an interesting subject. I know many um...smokers of other-than-tobacco use them for long term storage. While I don't think it's really necessary (after all, the first thing I usually do when popping a tin or opening a jar is to pull some baccy out to dry), I'll bet it would be great for those who have multiple tins/jars open at one time. That's where the drying danger is, at least for me.