You can have the controller return a list of addresses in the model and then tie them to a select.tagx to create a dropdown for the address on the order form.
You can use Web Flow, with sub-flows the user can choose to add/update addresses, phone numbers, etc.
As for being the starting forms being useless, they are for the end-user, but for the developer you get a fully functional application that allows you to work with data right after roo generates it. Instead of having to create it yourself. I believe Roo's objective is to quickly get a project started, there are way too many variables for Roo to make a production quality application, just using the "schema" the developer provides.