I think that in most places "Winter Wheels" are a bit of a waste of time, I take the same view with regard to "Winter Bikes". Yes where there is snow and slush I can understand wanting a stronger rim, more spokes and heavy duty tyres. I want to get the most out of my carbon bike and my carbon wheels so use them all year round, the cold weather and rain has yet to make any part of my bike wear out or fall apart. Why would I want to put heavier sluggish wheels on my bike just because the temperature has dropped a bit and it might rain. Same goes for tyres, Michelin Pro 3 Race or Continental GP4000s work for me, just as well in December as they do in August.
I think we sometimes get hung up about our precious equipment, it can take a lot more than we give it credit for.
Obviously if you live in Alaska or Norway or some other very snowy country it's a different story.