There’s also an element of “past performance is not a guarantee of future results”. It’s possible that someone correctly confidently predicted one thing for exactly the right reasons, and then confidently makes an error in the next thing for almost exactly the right reasons.
Likely, even, because the people who are confident about hard questions are more likely to be overconfident than have superpowers.
I understand that there’s certainly an information-theoretical security flaw, but if there is an attacker who could gain net value by seeing your mouse activity, you should be in a secure facility that prevents eavesdropping and none of the computers allowed in that area should be allowed to have bluetooth trancievers.
If a given dongle can be spoofed into providing arbitrary HID input (or just arbitrary keystrokes, in addition to mouse movement and clicks), that would be a more serious vulnerability.