The worst obstacle and the primary roadblock to using superconductors on Earth is the ambient temperature which necessitates a coolant like LN2 or even liquid Helium (and a lot of energy for creating these).
Achieving these temperatures in space is dirt cheap, a simple sun shield keeping the superconductor in shadow is all that's needed.
As I read the mass breakdown of some ion engines, the cabling contributed quite a bit to the weight. There's a lot of other applications where using superconductors would be superior. Maybe we could get ultra-low-power superconducting electronics. What about superconductor-based bearings for all the inertia wheel needs?
So why aren't they used more commonly? What are some other obstacles?