I think the biggest issue is that, at least quite a few years back, is that the methods of cryogenically preserve the bodies without ice crystals forming cause the arteries to weaken due to the chemicals used instead of blood. So if they were to thaw the body they would need a way to completely replace every artery in the body, or else they will rupture everywhere inside the body once they revive it. So basically the body is doomed to be unusable.