A good number of those don't have mandated return types, so that keyword is their way of copying c(++)'s look, so its "func main()", like "void main()", instead of just "main()", which to a some people may look strange.
I don't understand why this is relevant. Regardless of the rationale to add it to the language, if syntactically it's `func main()` I can tell it's a function definition because it's always `func`. You can't do that in C++ since it's often some type.
