WAV is to audio as BMP is to images: the fundamental, brutal, unsophisticated, first-effort approach that also, coincidentally, because of its brutality, somehow simultaneously represents an apex of fidelity and impracticality.
All other image formats get parsed to recreate either an identical or approximate bitmap as would have been encoded into the BMP file, but usually with more features or smaller size, or both.
All other audio formats get parsed to recreate either an identical or approximate audiowave as would have been encoded into the WAV file, but usually with more features or smaller size, or both.
BMP has the ability to hold compressed data too; for example they can hold JEPG and PNG compressed images. I don't think it has the ability to hold arbitrary data though.
One case is DJ equipment - FLAC support wasn't standard for a long time so DJs may be forced to stick with WAV to be sure of compatibility with the pro kit installed in clubs.
Also now that many sources provide 24bit audio you need to check for that and resample to 16bit to be certain it'll work.
Admittedly, I still use it frequently when I am too lazy to convert my CD rips to FLAC.
(Another fellow FB2k user here.)