Ah, that's true. I guess going back to normal vitals and motion is good enough for preliminary experiments, but of course once that step is over, it's crucial to start examining the effects of preservation on cognitive features of mammals.

Tardigrada and some insects are in fact known to survive ridiculously harsh conditions, freezing (combined with nearly complete dehydration) included. Thus, it makes sense to take a simple organism that isn't known to survive freezing, and make it survive. I suspect though that if you can prevent tardigrades from dehydrating before freezing, the control group won't survive, which means that some experiments can possibly be done on them too.