Friendship is not gender biased. If your insanity level almost matches the other person then you can be best friends forever.
True, Couldn't agree more.

Me being a boy, I can only talk about the male part of the friendship.

1. Your girl bestie helps you in mingling with a random crowd in the party.
2. She'll help you understand a girl's emotion.
3. She will guard you from the wrong girl.
4. She splits the bill.
5. She lets you go through her wallet/bag
6. You can be open to her

And the most important thing is she won't judge you for who you're.
These are really sweet gestures, Lucky you, You have got a great best friend.