TECHNICALLY flac is conceptually worse than wav. Flac truncates the 0 values in the PCM file, WAV preserves them. It's functionally the same, but wav reads the file while flac has to re-add the 0's then read the file, so there's technically one more processing step (which could go wrong).
That's kind of like saying storing files in a zip is worse than storing them uncompressed.
Or like the "what color are your bits": https://ansuz.sooke.bc.ca/entry/23
Kind of, except anything that moves can not move, so the simple act of decompression can introduce errors that simply wont occur in the raw PCM-wrapped WAV file since nothing has been compressed at all (hence no extra moving part).
