Programmers often discover solutions while explaining a problem to someone else, even to people with no programming knowledge. Describing the code, and comparing to what it actually does, exposes inconsistencies. Explaining a subject also forces the programmer to look at it from new perspectives and can provide a deeper understanding.
It’s a moron detector.
Most of us would avoid it like the plague, but morons will let it write their code in the first place.
Amen.