They're not made for that. You use skis or snow shoes if you have to walk long distances in deep snow. Footsacks are for when you dismount the skis/snow shoes to do whatever work that needs to be done (campfire, shelter, snow cave), standing still and stomping about in deep snow.

I would guesstimate that the footsacks probably would wear out over a few weekends if you used them walking on weekend trips.