Nah, they don't do anything on the steering, at least nothing that folks have reported or testers have noticed. They are extremely light, and since the hub of the wheels doesn't have to put up with larger torque loads that a more normal rotor (two for most bikes) would generate in the center of the wheel, the wheel is light as well. They are very thin in width compared to a normal rotor but might not be too good for racing with heat etc. They do stoppies all day and look cool - I think that is the biggest reason Buell chose them!
There are a lot of neat Buell features such as gas stored in frame (not new, but just not in use much these days), oil for dry sump in swing arm, muffler located under bike (some 600s are getting into this now) instead of pipes up high, belt drive - no more chain to adjust or lube, and some other "light" things. Certainly no sportbike by Japanese standards but a cool torquey ride for ripping around and communting.
R