> This format doesn't really blaze new ground (EDIT: it does in the sense that it defines a container format to express image-y constructs like still images and sequences of images in an ISO media container, but see my other comment that asks how this is similar but different to video [3]), but if this repackaging and the resulting code donation and political clout helps it gain traction, we still would gain a lot.

You need to think about HEIF as the container and disconnected from the codec used to compress the media content. In that sense, HEIF is a massive trailblazer. It gives us an ISO standard to describe image and mixed media consistent with existing methods (i.e. MP4) while allowing for new constructs (i.e. useful features of the future in addition to tiling, depth map, stereo, etc.) and new codecs as they are developed and adopted. HEIF is a universal forward-looking format.

Until now, almost all of the major imaging formats were tied to the codec and not terribly extensible to new use cases. While BPG is a great format in the short term (it gave us HEVC coded images around 2.5 years ago), it isn't an ideal choice for the long term when viewed as above.