Why Do Women Shave Their Head Bald?

Fair enough if you have a disease or are going through chemotherapy then you don't have a choice, or maybe to support a family member who is going through the same then it's ok. But most women are really upset about losing their hair and grow it back straight away. So why do models and good looking women (the south african women's captain at the world cup draw) shave their heads. i'm not talking butch women im talking women who have really beautiful faces but are completely bald. it looks horrible. a women with a bad hair cut looks better than a bald one. Maybe for convenience, but for models (e.g fight for this love video), why would you go bald. What do you think?