My point is that, if the 9-tails innate ability is to heal, which everyone marvels at, why not learn to draw out that ability to heal himself while using its power to fuel the Rasen-shurrikan. Naruto damages himself using his own chakara, and then heals after using the 9-tails. Why not use the 9-tails to form the RS and counteract the damage to begin with???
Naruto's body only gets damaged when the tails start to form. You can't believe that Gara was damaging his body, just by the sand acting by itself. The difference with Naruto, is that he can control the 9-tails chakara at this Pre-1tail level, while Garas' acts on its own. Take this to the next level...
Gara's sand technique was formed by the demon's chakara manifesting itself into a usable technique. Naruto is only able to manifest the 9-tails into a physical form of chakara (the Demon's Cloak). While, Naruto has learned to turn his own chakara into physical forms, IE Rasengan, and now Rasen-Shurrikan, but he doesn't use the demon's chakara for it. Which ultimately sets him apart from other Jinchuikis.
Kabuto and Tsunade both have techniques that heal themselves, while doing damage in the long run. Just because it does damage in the long run, doesn't make the technique horrible to use. Kabuto was going to die from Naruto's first rasengan, but he healed himself as it hit him.... Along those lines with Naruto using the RS.
In the end, its like this analogy. If you are on a desert island, would you drink your own urine to survive? It will harm you in the long run, and you will die from it eventually, but you will survive longer.
