Aside from the calling of maps/strings, which is already puzzling, have you considered how strange and limited the forwarding of parameters is?
It expects that developers usually don't change parameters as it passes through functions, especially its order, there is so little flexibility, it's shocking it's designed by an adept programmer who takes this feature for granted in typed languages.
By the time you have finished planning the Functions Maps, you have ended up spending more time changing the events than it would have taken to just write 1 to 3 lines of JavaScript to do the same thing, with better readability and flexibility to adjust with little changes in the event sheet.
I mean, it's proof enough that people are willing to use JavaScript to call functions with strings rather than use the built-in. People would always find the more convenient option.