The fuck? Most formats are more complicated than TIFF. TIFF is so simple, you barely have to read 30 pages of well written spec to modify it with just a hex editor. You don't get much simpler with a binary format. Want something complicated? Try implementing PDF with it's hundreds to thousands of pages per version.
I don't know about fax machines but a lot of scanners used it. You can also have multi-page .tiff files of lossless images, though they're generally huge files.