If you return a function, the compiler has to bundle up the values of any variables that the function uses from its outer environment and return the whole packa

If you return a function, the compiler has to bundle up the values of any variables that the function uses from its outer environment and return the whole package. That's known as a closure. You can't just return a function pointer. Basically, if you don't return functions, you can avoid dealing with them "escaping" the lexical environment in which their code lives.