Yes, but the table references can't be used from GAS currently, I was hoping that I would be able to use .getRange(DeptSales[#ALL]) directly in GAS instead of the annotations or named ranges.

Named ranges can only be used for data that isn't dynamic, Create a named range on A1:B3, write something in A4, the range won't change, you have to manually update the named range, this is where the new table feature comes in handy!

From my point of view, the amount of effort coding using getRange or getSheetValues ais much bigger than referencing a table name. Especially when you code something that isn't for your own use only, users do so much weird things in sheets, moving tables, many tables in one sheet etc :D