In C2 it was possible to call functions by name. You could do things like Call Function choose("SpawnZombie","SpawnVampire"), or even Call Function "Spawn"&choose("Zombie","Vampire")
In C3 it's not possible, you can only pick function name from the list. That's why function maps were added.
Of course, in your example it's easier to just use a function parameter. But imagine you have several large functions with very different code and you need to call one of them dynamically by a string name.
Having said that, I haven't used function maps myself, I find this concept too complex and cumbersome.. I still prefer to use a bunch of If-Then-Else blocks.