While dangerously high levels of space radiation are a threat as you described, I think a more immediate scientific breakthrough comes from studying their water regulation in freezing temperature. Somehow, their cells, which are mostly water like human cells, are able to withstand freezing temperatures without forming ice crystals which normally destroys cells. Understanding the differences in their cellular temperature regulation in extreme cold could give us clues about the feasibility of cryopreservation for long distance space travel or other medical purposes on Earth.
RE: [TIL] The Invincible Water Bears and How They Will Help Get Us To Mars --