WebP fail
HEIF is all well and good but it's impact in the real world will be limited. Apple could have done its users a bigger favour by including support for the WebP format for bitmaps in Safari. When it comes to photos and videos on the interwebs Apple is a much smaller player than Google. Using HEIF with HEVC for bitmaps is unlikely to take off because, unlike WebP, HEVC is encumbered which will dramatically limit the spread of applications that can create the files.