This seems like a simple question with a simple answer.
“Because it is a nice thing to do!”
“I get to help a child in need!”
Which is all true. However, you may not realize that by donating your hair and having it be made into a wig. It gives children suffering from hair loss because of some medical condition some sense of normalcy and confidence. I am sure when we were all kids, many of us wanted to fit in and make friends. However, bullying is not uncommon and having no hair may bring an unwanted attention, especially for girls. They see princesses, actresses, or cartoon characters with long, flowing hair and cannot relate. They can feel sad and feel like they cannot be as beautiful as the girls they see.
The medical condition may be a challenging obstacle already which can not only take a toll on the child but the family as well. Medical bills and procedures on top of seeing their child suffering may be hard on the parents. Non-profit organizations that provide wigs for children for free or for little cost is a relief for the family and gives that child a sense of confidence and normalcy in their life. So they can feel like a kid again.
Side note: I believe this is a good alternative if you are unable to donate blood for some reason (like me) and want to give back to the community in some way. Check it out girls and/or guys!