Except for one thing. As the video showed, quantum computers act in such an entirely different way that there is no way to compare them with regular PCs. Certainly, if they can touch other universes, they might be able to find all the pieces of the blockchain elsewhere, other than the blockchain right here. then, all that they need do is bring that info home to Mommy.
Look up post quantum cryptography.
You can start here:
http://nvlpubs.nist.gov/nistpubs/ir/2016/NIST.IR.8105.pdf
About transmission speed look up quantum teleportation and data transmission.
Hey! Thanks for the link. I think I have seen it before. So have all the developers of quantum computers. That's why government authorizes stuff like this, and why developers go way beyond it.
Since you like links so much, here is mine:
https://micahflee.com/2013/01/no-really-the-nsa-cant-break-your-crypto/
The NSA may not be able to break Bitcoin quite yet, but this video courtesy of SulmaINO (https://bitcointalk.org/index.php?topic=1578776.msg16209756#msg16209756) shows that they will be able soon.
https://www.youtube.com/watch?v=JhHMJCUmq28