re: #22 windsagio
ah, those would be “boot sleeves” or “boot covers” of which there are many colors and styles.
Why? I don’t know. I suppose they originated as a way to keep your boots clean —way back when boots were hand made and you only got one or two in a lifetime. Or to make them serviceable thru-out the year . . furry covers kept you warm, etc.
Now, they are a fad —just like anything else.