Im just wondering what can a programmable xBee do that a non programmable cant dO?

The programmable XBee modules add a 2nd processor to the board that allows you to write and upload code to. This means that it can perform any function or process that would you do with an external processor of the same capabilities. This is something that the standard module just does not have the ability to do.

To clarify, the programmable version allows you to perform any function or set of instructions that the standard RF processor and its related firmware is not supported.