When healthy, it is visually attractive, and can be colored and styled in so many beautiful ways.
Even better, it is wonderful to touch! You can put your hand on your lady's back in public and feel the softness of her hair in a way you can't touch her ass, legs or tits.
But the best is to feel her hair on your skin - face, arms, chest, stomach, cock and balls! It's the softest thing and it feels amazing!
I first experienced that sensation with fur. As a kid I had a raccoon tail at first, then later got some fox fur scraps on a tour of a furrier. I'm not exactly sure how that transferred to long hair, but there was a series of letters in Penthouse Forum in 1974 and 1975 on hair fetishes that sealed the deal for me.