General

So in an effort to think up more sustainable footwear, I stumbled upon a concept of a sandal that goes over shoes. This was being marketed towards "sneakerheads" I think, or people with nice shoes. My use case thought with this design would be, you put on the "sandal" to walk some distance (maybe you need to walk a mile each way to an event) and then you take them off for light walking arount at a destination. This would allow the "sandal sole" to be worn out faster than the shoe itself.
 
I've looked in to the idea of "resoling shoes" but this looks complicated. So I was wondering instead if you could just have a sole that attaches as a sandal (sandal sole) that could be disposed of or reused when it gets used up. Or you could design shoes this way where the sole attaches like a clip in sandal so they're easily replaceable.
 
Redundant concept? Not useful? Got an alternative idea?