The quantum stuff cannot reasonably called "pure" speculation because we have evidence of "weirdness" at tinier scales in the universe that open the door to woo. Doug Matzke kicked the door wide open and inside I found Penfield, Russell and Burr. You're not able to point out problems with points they make because you haven't read them.

Chemo/gluteraldehyde/ASC/upload/ai/cryonics/vit'n are all based on the speculative idea that memory and personality are embedded in brain structure. That is speculation too and the entire preservation/reanimation industry is based on it. I see and understand the evidence for it obviously but if the mind is a dualism phenomenon, not monist, then it won't work just like freezing a TV set won't trap Star Wars, Johnny Carson and Fred Flintstone inside of it.

The brain is an antenna. It's not a memory module, although components of memory may exist within it to operate the meat-body-brain-machine.
The idea is the brain recieves signals from the quantum-presence where we exist right now. Its a materialist projection, a sort of puppet, animated by the invisible quantum hand/soul inside of it. We are ghosts in a machine after all.

A lower cost way of preserving the antenna is interesting to someone who might be interested in storing TV set in someone's basement rather than a storage facility, but it's still a receiver.

The danger lies in not understanding that the upgrade to the quantum self is in the acquisition and comprehension of experiences gained via the meat-body-mind projection we're currently in, which could very well be a simulation anyway. The danger would be in not understanding that we're currently gaining experience to generate a higher quality experience in the next projection.

Either way, there is speculation. I'm currently speculating that we're already immortal. I would also speculate that you won't be reading Matzke, Russell, Penfield, and Burr.