Now we only have a secondary function for the "keyboard function".
Imagine if we could combine inter-device functions with mouse functions (and other ones).
For example: to set a key to a function to "Right click" and a secondary function to use "Inter-Device" setting the user's mouse to another DPI while the key is pressed.
Another example: is changing the color of a key in the first function while the second function is running a macro (this would help visually to know if a macro is enabled or disabled).
One more example: there are games where you have more than one way to play, like fighting games. You press a button that changes the move sets/fighting style. Normally, the fighter makes a movement or hit, and then all his move sets change. Imagine the first function being this movement/hit and the secondary function being a Switch Keymap function.
These are only some examples, imagine all you can do by combining all functions in pairs.