Not a waste of time for me. It (having one) has been the determining factor on whether I'd sell a pistol to someone in Atlanta who doesn't have many good reviews and is very young. Don't like it? Tough.
Yeah I've seen a lot of people in ads request that the buyer/trader must have a GWL. Every person that had that in their ads that I have purchased from or traded with has never asked to see mine, even though I do have one. Must just be a in-person vibe thing. I've personally never asked to see one either, as owning a firearm is a God-given right in this country, not a government given right.