What's the point of battle.net?

Perhaps this will help a little with explaining the purpose of the new battle.net:

http://us.battle.net/faq/index.html

Q u o t e:

Q: What are the benefits of creating and using a Battle.net Account?
A: The new Battle.net Account allows you to log in to World of Warcraft, manage purchases at the online Blizzard Store, keep track of CD keys for your Blizzard Entertainment games, access our websites (such as the World of Warcraft Armory), opt in to upcoming beta tests, and more using a single login -- just your email address and a password. In the future, we plan to add more features, including tools to make it easier for friends to communicate between games and to help bring our community of players closer together.

And additionally:

Q u o t e:
Q: Is creating a Battle.net Account required to play World of Warcraft?
A: Currently, creating a Battle.net account and merging World of Warcraft accounts is entirely optional. However, as we continue to build additional functionality into the new Battle.net, we will eventually require all active World of Warcraft accounts to migrate over to Battle.net Accounts in order to continue playing. Additionally, all future Blizzard Entertainment games such as StarCraft II and Diablo III will require Battle.net Accounts.

Q: Why will Battle.net accounts be mandatory to play World of Warcraft in the future?
A: With the upcoming releases of StarCraft II and Diablo III, having one unified account system allows us to ensure the highest-quality user experience and customer support for our players. In addition, the new Battle.net Account system will give World of Warcraft players access to certain future Battle.net service features and updates (as applicable).

Q u o t e:
Thanks for the info, Neth, though I am a little skeptical of the battlenet accounts, since I keep hearing these nightmares of people getting hacked after switching over.

I guess I'll just hold out as long as possible.

I can't vouch for the validity of these claims, and it's sad to say that some people will say things just to stir up problems and create confusion for others with false claims from time to time. I can say that we are very aware of the security concerns and continue to work to ensure the safety of all user accounts. For those that may not know as well, you can tie an authenticator to all of the World of Warcraft accounts that you have under your battle.net account and it can work for all of them. This should help to alleviate some concerns. As always, for those that think they may have had their security compromised for their account and believe there is activity going on with their account that they have not perpetrated, please contact our customer service team and they'll do what they can to help.

Also, there are more things that we'll be able to talk about a bit later in regard to additional benefits and features for battle.net mergers that we hope everyone will enjoy. We're just not ready to discuss them or release them at this point in time.

For those that play any of our other games, being able to store your CD key and be able to re-download the game should you lose a CD is a great convenience.

Q u o t e:
A question regarding this. I only have 1 account, but my boyfriend has 2. If he merges his accounts with the battle.net and only has an e-mail address for a username, how will he determine which account he wants to log in to?

There is a window that he will be able to see when he logs into World of Warcraft that will let him choose the account he wishes to log into.