The actual effect on performance is small, absolutely. That wasn't my point, my point was that a lighter bike will feel dramatically different (usually it takes more weight off than 1/2 lb to notice this in a major way). You can argue about it being about geometry if you want; I've ridden a zillion different bicycles of different weights and geometry, and the weight matters a lot. All things being equal, a lighter bike feels nicer to ride. A bike that is nicer to ride is one you might ride more often. A lighter bike is certainly one that is easier to deal with when you aren't actually riding it. I include wheel weight within the total bike weight, by the way, in the context of the OP there's no point in treating them separately.

I really think the backlash against the urge to reduce bike weight gets a little out of control here; why, when someone posts that they would like a lighter bike, is it necessary to resist so strongly? What's wrong with wanting something a little nicer? It's frankly weird that anyone here might need other people to also ride heavy bikes to validate their choice of bike. Frankly, who cares? I'm not going to get after anyone here to swap out their current bike for something that I would prefer or that's more similar to my bikes. The rush to condemn any desire to drop weight on the bike here is kind of pathological at times.