People who have business trips that last longer than a week or so! And there are a few of us, at least.

My most common trip is 4 - 7 weeks. In that period, there is usually some change in season. Packing now for Chicago. The leaves will turn and fall while I am there and I bet I will see a temp range from 60's to 80's.

Also, I like to have my own stuff and did pack quite quite a bit heavier than I absolutely need to. In for a penny, in for 50 lbs.