[nothasan]

It’s not just cybercriminals who want to MITM. There are nation states who have been tapping fiber optic cables for a long time.

[haimez]

https://www.usenix.org/system/files/1401_08-12_mickens.pdf

If you have a mossad problem, big integers were never going to save you from that before or indeed, after QC.

[riffraff]

Sure but the average nation state does not need to steal my bitcoins.

OTOH the typical cybercriminal wouldn't have access to quantum computers for a while so this is a pretty unscary prospect either way, for now.