observe the paper read out from a seismograph. all those squiggly lines. now add resonance feedback from playing music over the top of that. now add any industrial noise, or traffic noise, or waves or even airplane noise.
all those things are the resonance noise floor of your system, and that is adding background noise to whatever you hear. so it subtracts from the purity of the music reproduction.
it effects the racks, the electronics, the cables, the sources, and the speakers. might be more obvious and easier to understand in a turntable where the stylus is reading vibrations, but it's effecting everything.
you can eliminate almost 100% of that.
and electronics are definitely affected by that noise. the noise reaches your speakers as distortion. and that distortion locates the sound as coming from your driver, instead of from the music in the soundstage. so it lowers the realism. lowers the immersion of the music. adds an edge, masks detail.