Comment by lozf

Lossy codecs use psycho-acoustic models designed to encode music so it sounds okay to humans, by discarding frequencies that we're less likely to hear due to masking etc. -- Just need to avoid those frequencies.

Having said that the newer lossy codecs (e.g Opus and some AAC variants) which are more efficient (sound better at lower bitrates) and have less "problem samples" than MP3 would perhaps also be better for data use, like they are for music.