Currently, address attributes are not fully implemented in the system. In particular, they are not shown when a customer registers or on the customer info page.
We use three address attributes to qualify the type of address for shipping. These are implemented as three pairs of radio buttons, and they're marked as required. When the customer registers, no address records are created for the customer, as the address attributes are missing.
So, let's say someone new comes to the site and finds something they'd like to buy. They go to checkout and are asked to either sign in or register. If they register, they are presented with a page where they get to fill in the information, including the address. If they then continue checking out, they'll find that they need to enter the address again due to the missing address attributes. This is just dumb.
I seem to be hitting problems like these more often all the time now. Too many new features are not fully implemented. When address attributes were added they weren't added everywhere. They should have been.