The best silicon single crystals still contain impurities at the 1E-11 level. This project is about doing crystal growing in low gravity (the ultra-high purity is only achieved due to the growth process). The vacuum of space is a lot worse than what can be achieved in the lab, especially in low orbits.
I had a similar thought regarding radiation - but also curious about cost to continuously launch materials and the overall reliability of recovery. Just seems like a lot of "what ifs" for the sake of finding funding.
