Sometimes here on Scripting News we get the news before it is news. 

Andy Carvin asked Eric Schmidt why they only accept real names. He said it's because it's an identity service. 

On 7/26/11 I wrote that Google-Plus is a bank.  

They want to move money around the same way Amazon does. They need your real name because it's a business. 

"Google-Plus is their integrated communication system. Over time, it's going to be at the core of everything they do, from auctions, to paying for things with Android phones, to their groupon and yelp clones. They're going everywhere, and this is the system that will tie it all together. So, at the outset, of course they need real identities. That Google-Plus account you're playing with today is going to be your bank account next year."