Why functions need a parameter list to compile?

Is this just the way it is in Max?

If I don't put a parameter list it throws a

No parameter list:

Function bmpZeroToNine:Int
	Return 22
End Function


Local num:Int
num = bmpZeroToNine
Print num

Parameter list:

Function bmpZeroToNine:Int (x:Int) 
	Return x
End Function


Local num:Int
num = bmpZeroToNine(22) 
Print num

This shouldn't be should it?

needs ()

you can have this, if you like :

Function bmpZeroToNine:Int()

But the () are required syntax.

okee dokee.