All papers should be in HTML/CSS or Tex then just simply converted to PDF.
Why are we even talking about this?
The problem is having the submissions be in TeX and converting that to HTML, when the only output has been PDF for so long.
The problem isn’t converting HTML to PDF, it’s making available a giant portion of TeX/pdf only papers in HTML.
If you’re arguing that maybe TeX then shouldn’t be the source format for papers then I agree, but other than Typst (which also isn’t perfect about HTML output yet) there aren’t that many widely accepted/used authoring formats for physics/math papers, which is what ArXiV primarily hosts.
The idea was to seek spots in the city where public web cams are pointed at, and paint QR codes on the ground at those spots (using a template), linking to the camera stream. So when curious passerbys scan the code, they see themselves in a camera stream and feel "watched".