Only a laymen’s experience to share. The experience is one of psychoacoustics. Creating enough of an illusion that make it easier for you to imagine depth. Width on the other hand is a function mostly of the recording engineer when balancing between left and right output for a given signal/instrument.
For an amazing image width illusion (no idea how/why it works) listen to Roger Waters album, Amused to Death. Just the first 2 or 3 tracks. You’ll hear a dog barking far to the right of your right speaker. Almost as if it’s coming directly to your right side. You’ll hear spoken dialogue (track 2 as I recall) that comes from beside you to the left. I use that album to set up my speakers. The illusion is almost spooky when dialed in.