From a good loudspeaker, white noise sounds very shrill because it is mostly high audio frequencies. Pink noise sounds more pleasing because the high frequencies are reduced by 3dB per octave, something like interstation noise heard on an FM radio (where de-emphasis cuts the high frequencies).
When I worked with a few office sound masking systems, workers thought it was air conditioning or water running sounds.
I saw a half dollar about 50 years ago. It is much too small for a loudspeaker, it would just make squeaking sounds. It is suitable for a sealed headphone.