Z is the most popular rubber Rakza rubber. As for the graph, it's just a comparative trajectory illustration for spin vs speed. It doesn't mean that in real life your trajectory will be nessessary that high if you adjust your technique. I have had RZ on 5 different blades and I've learned that it's quite picky in that regard. Nittaku Ludeack/RZ for example wasn't a good match. But RZ had great synergy with some hinoki carbon blades which had a lower throw. With a Darker 7P-2A.Carbon the trajectory is as flat as you wish and there's almost no bounce, the ball is gliding forward with lots of spin. You just need to close the racket more. RZ is so tacky/grippy, it requires some extreme angles and this makes it a bit harder to play with. But it rewards you with some ridiculous spin which your opponents will underestimate time and time again, and great control over the table. And with lower level opponents I sometimes can't help but return a higher, short, heavy backspin just to tempt them to "flat hit a line of sight" as you say. And I know 8 out of 10 the ball will hit the net. So RZ is all about the spin. If you're not careful and try to drive-spin it with an open racket, then yes, the trajectory and the bounce will be too high. In that respect R7 and RX are easier to play - both for you and your opponent shall I say. I never tried R9.More non-sense. Who would buy the Rakza Z if the ball bounces up so high the opponent can just flat hit a line of sight shot? The shown trajectory for the Rakza 9 is the best. Low and doesn't bounce high. Also the path is shorter to the end of the table so the opponent would have less time to react.
BTW in my view the pic is not quite right about R7 vs RX, the latter had a flatter arc and was a bit faster. But maybe it's just the lade.