Two channel with two speakers, separated by a good distance, will create the 'stereo field' effect, which is like sitting in front of a stage of musicians.
The sound mixer will generally put the singer, bass, kick drum and snare drum in the exact center. After that he can pan left and right different instruments and backing vocals.
Sadly people buy single speaker units where the left and right channel speakers are so close to one another that there is no stereo field.
Stereo is worth the effort of having two speakers.
I get the feeling this was not well appreciated when in the late 70s band would PAN the sound back-and-forth.
Loved Emerson, Lake and Palmer back in the day, and they did a couple songs that panned a lot, not to mention Beatles, etc.
I enjoy isolating instruments on the L or R, but maybe it's not a great representation of how they really sound.