Yeah, but I'd call that 'remnants of El Torito'? You basically have tooling to burp out the MBR, boot catalog and UEFI FAT32 shim, all pointing at the native code that can read your actual (very-much-non-ISO9660) file system into RAM and bootstrap it, and you're good to go on USB, ISO, or whatever.

The first 3 parts aren't that complicated (literally a few sectors with fixed content, maybe a few pointer fixups), and no reason IMHO to want to kill off ISO. Generating that actual file system is the hard work, but also required for live-USB distros, which circles back to the point being made in the article eluding me...