Probably to save time detangling!  I have thick, natural shoulder length hair and if I wear it down it will tangle up.  If I don't braid my hair up at night or when washing my hair I have the same problem.  Braiding definitely makes the hair more manageable if in a long natural style.

I wonder if it was a self esteem black thing on your mother's part?  You know "if my daughter's hair is all braided up then I'm doing right by her?"  It's probably no different to the school of thought of refusing to let your child out with a dirty dress or grubby face.

 I am mixed race with a white mother who didn't know how to braid and growing up in the UK I used to feel so jealous of the black girls who had their hair up in elaborate braids.  They looked so pretty whereas my hair worn down looked so uneven and messy. 

R2D2inoz  

I remember when I was little my hair used to get braided at night. It saved time to have it already styled and just have barretts added to it for school. Also, I loved the crinkles...sometimes I asked my mom to let me hair get crinkly so I could wear it wavey for picture day. 

When I try to wear my natural hair out for more than a day, it gets tangled faster and it takes time trying to get the tangles out. That is probably why our parents braided our hair at night. Plus...since it is passed down from generation to generation it does give you a since of who u are and where you came from.  It connects us to each other when we have certain traditions such as the braiding ritual.

My hair was ALWAYS braided with beads.   And I remember always asking to wear it down.  But now that Im natural again, I see why my mother didn't let me wear my hair loose.  It tangles like a Mug! 

And back then my natural 3c hair reached my behind!  And yeah, she use to tell me I was too young too.  Now I know what she means. 

My neice has beautiful sandy blonde 3b hair (which tangles like mad) and I would never let her wear her hair loose now!  She's definitely too young. 

And by that I mean, she doesn't know how to act when its loose.  She goes runnin' around shakin' her head, flippin' her hair back and forth until its all tangled up again!

Leave in conditioner can only do so much...if you lay on your hair while its loose no product is going to keep it from smashing, right? U have to reshape it or comb it out when you wake up, correct?  Besides, using leave in conditioner everyday is just as difficult as combing the hair out everday anyways...thats why young girls wear braids to have less days of detangling.