Silicone blades do NOT do the same thing as Rain-X.

They do not leave any kind of coating on the windshield (silicone has a high degree of chemical inertness, thermal stability and resistance to oxidation)

Silicone blades simply work better through a wider temperature range, and are more pliable.

I've had the SilBlade wipers on my X for a year now, and they pretty much don't work any better than a set of Bosche rubber ones. Nothing but streaks and smears.