Why is it recommended to use cold water for curly hair?

I've been reading over a few tutorials on how to tame, straighten, or take care of my curly hair. Almost all them mention using cold to warm water to ';lock shine in.'; What exactly does cold versus warm water do for hair?Why is it recommended to use cold water for curly hair?
well when you put warm or hot water on your hair it opens up your hair strands and they take in things you put on them (why you use warm water to shampoo your hair, your hair takes it in making it cleaner). When you put cold water on hair your hair closes up (why they tell you to put cold water on it, it locks it in) So, when your washing your hair do a cold water rinse when you done, it makes your hair less frizzy and shiner lookingWhy is it recommended to use cold water for curly hair?
Even though I dont like how it feels rinsing my hair in cold water, the times I did do it, it dried a lot softer and it was a little more manageable. I think the hot water damages it, and also makes it less shiny. Cold water will make it more shiny for sure.
to keep hair from frizzing and to keep the humidity in it down. even just ending your shower with like 30 seconds to a minute of colder water will help because it will seal the cuticle and help keep the hair soft and indeed shiny
I believe that cold water helps to close the hair cuticles and makes hair shiny, softer, healthier, and less frizzy.