Want.
I looked in to some third-party "moon" discs before I bought my car a couple of years ago. A query of mine got forwarded to engineering, and the official response was to frown on the idea both to the potential for scratching the wheels and for retaining too much brake heat.
However, if you only use them on long highway trips when you are not using the brakes, and they are easy to take off in town, they might be OK. I'd err on the side of caution, though.