Yeah I heard about this a while back. Looking at that article it was dated back in February.

I think more than re-selling registrations, they are using the role as a registrar to mine the data available as a registrar. What they might be using that information for is anyone's guess. However, they do love data, and becoming a registrar allows them access to more of it. All this time later, it does not look like they have done anything publically with it. However, since Google owns a vast number of domain names, it probably makes sense just from that perspective to become a registrar.