Good point, the names really don't matter and the first type could as well have been a string. I just wanted to illustrate the concept of using the type system

Good point, the names really don't matter and the first type could as well have been a string. I just wanted to illustrate the concept of using the type system to add important information and guarantees to certain variables. Your state machine analogy is a good one, because the conversion between different types is a bit like the transitions between states: you have to make explicit how exactly they are meant to happen (or whether they are actually possible). This is a good thing, having less degrees of freedom may seem like it makes it harder to code, but in fact it allows you to reason better about what the system is doing at any given point in your code.