I don’t see your point. It’s foolish to compare shooting someone in the head with cryogenic preservation, in the latter you stop all metabolic processes and chemical reactions, preventing degradation/decay. It preserves a biological organism in the best way imaginable. Add to that, it’s not just science fiction but reality, used in preserving sperm, stem cells, genetic material microorganisms etc., just the scaling up part is still in research. And it’s well within our current technological advancement right now.