What if the success rate for currently available devices is 0 percent?
Should we not make available something which succeeds in some fraction of cases?
What is the magnitude of benefit in cases that do succeed?
"Success" is literally just "doesn't kill and/or horribly maim you". It's not a treatment for a disease. It doesn't give you super powers. It offers no tangible benefit to the patient.
There should be an exceptionally high likelihood that the procedure will go well before any human trials are allowed to take place. They can't even demonstrate that they can reliably perform it in animals, so there's really no reason to press ahead in humans except to be able to claim some ridiculous velocity.