The inherent advantage to clipless is not having to use those God awful straps...and while they aren't the most comfortable walking shoe, my Keen commuter shoes (or the sandals for that matter) are comfy enough to walk a mile in without causing problems. Generally I'm not walking that far when I'm cycling, so a mile is fine.

Traps and straps are more difficult to ride with, harder to get in and out of and annoy the top of my foot. They're silly and I can't understand why anyone has used them since SPDs.