With SEQUENCE it's up to you to select the ID and insert it as a column value in your code. With AUTO_INCREMENT the DBMS does it for you. They both depend on a central DBMS to generate values. In both cases you can restore data. The IDs are just normal column values after generation.

As far as SSAN I'm not asserting it's a good key, just a natural key, which is to say a key inherent in the record.