This is simply the ability to import the field definitions from a table in one file to make a new, empty table in another. If this is your only reason for buying advanced, don't. You can simply use import records with "new table" as the target to import field definitions on regular FMP and then delete the imported records.
Features that make FMP adv worth every penny.
Script Debugger/Data Viewer -- has saved me countless hours figuring out why a script isn't working. It's especially helpful in diagnosing script triggers that may be triggering under circumstances that I didn't expect.
Database Design Report -- Flawed but still very useful for searching out "missing table, missing field, unknown..." type broken references.
Run Time DB creation -- allows me to send potential customers a "demo" verson of our product for evaluation.