At 1:30 in that second video, he shows that YouTube already converts dot zip domains, even in old comments that predate the domain's existence. At 3:19, he shows/mentions Twitter, Reddit, Facebook, and LinkedIn. I would consider those major platforms. And keep in mind, it only takes one person downloading one file to cause major damage - the LMG hack was due to someone downloading and trying to open a fake PDF that was sent via email: https://youtu.be/yGXaAWbzl5A.
So yes, not everything does or will auto convert the links, but I think you are underestimating the potential for issues here.