1 - The ability to create tables and indexes from code, instead of using the control panel. Example where this could be useful: Dynamic creation of game "zones" where you want each zone to have it's own table.(just a small example, i can think of a lot more cases where this could be useful)
2 - A button to truncate tables in the admin panel. When i'm testing code i often put a lot of junk on tables, when i want to clear it out i have to delete objects one by one. I could also delete the table and recreate it, but then i would have to recreate all the indexes too by hand.
3 - The ability to import data back using the exported data file from the admin panel. (i'm thinking about backups here)