An LoR is an educator, familiar with the student’s work, sharing with another pro in the education field.
Why not?
Grades, stats, etc, are only the bones. They can’t convey the style, eagerness, personality, peer relations, respect, and more.
Maybe LoRs are useless for colleges that rack and stack, admit that way. But for holistics, a rec is an eye on the kid. Why not?