To a bitcoin purist, ripple is unnecessary.
I highly doubt 99.99% of humanity will ever fit your definition of a "Bitcoin purist". However, I can't be sure because I have no idea what you mean.
Can Ripple help Bitcoin grow? This is what's important.
All of the theoretical solutions out there are nice, but what matters is the solutions as they are. Bitcoin and Ripple provide real (prototypical) solutions.