Depends. Let's say, I want to first plan a tour around the challenge cache and grab as much caches as I can. Then showing "all caches on red degrees 10 km around the challenge cache" would be great.
Absolutely perfect would be: Showing the red degrees via greasemonkey as a layer directly on the geocaching.com-map (or any other map, e.g. from GSAK). I have boundaries (state/county) as a layer on the gc.com-map and it's great for planning.