The point is that if you’re prepared to record a macro and then dissect it, you can find out what the command is that the property triggers, and you can then manually graft that command into your keycommands file.
There are two more detailed write ups of the process here: Dorico 3 - Keyboard shortcuts for microtonal accidentals? - #5 by pianoleo
The scripting functionality is largely incomplete, so there’s not yet any documentation for it.