1. As long as we don't pretend this is an attempt to 'solve' global warming, it seems a viable alternative. It's been pointed out many times how little petroleum is used in manufacturing plastics et all, it would undermine the argument for their use.
2. It will ultimately become necessary to be able to produce these materials in industrial scale and I don't know how long it will take to ramp up to that.
These are minor quibbles comparatively. As a proponent for nanotechnology myself when applied properly, I hope it does work out.