One of the advantages of hooking the mittens to the sash is to get them out of the way. During vigorous exercise such as snowshoeing, I often find the mittens too warm to wear but I don't want them flopping around about my arms. The same is true for any activity where I use my hands a lot but it is too warm for mittens. I often will slip on a pair of light wool or poly gloves while active and when I stop or the temps have really dropped, my mittens are handy and the wool gloves stash easily in a pocket.