I've seen commercial sites hard-code gzip content in all their responses regardless of the Accept headings. Probably just as fair to use Brotli these days.
Similarly, I've been using zopfli (gzip/unzip compatible) for png compression after quantization for db storage from 2-color (B/W) scans as it's directly compatible to the browser but winds up about 1/6 the original sized tiff. Not the best compression, had a discussion for a better compression, but required a wasm renderer to decompress as it isn't in the browser box.
Similarly, I've been using zopfli (gzip/unzip compatible) for png compression after quantization for db storage from 2-color (B/W) scans as it's directly compatible to the browser but winds up about 1/6 the original sized tiff. Not the best compression, had a discussion for a better compression, but required a wasm renderer to decompress as it isn't in the browser box.