[tialaramex]

Those "things that look at a lot like strings already" are literals and thus constants, with the type `&'static str` which is how Rust spells an immutable reference to a string slice which lives forever. So, Rust is promising that the string slices "Hate Me" and "Blue October" exist, and in practice probably if you look inside the resulting executable it says "Hate MeBlue October" or similar.

On the other hand the String type is a growable array of bytes used to assemble strings, it's an owning type, so Song will own those two Strings, they can't go away or be altered via some other force. Owning a string would allow you to add to it, change it, or discard it entirely, you obviously can't do that to the text baked into the executable, so if you want to own a String it will have to be allocated at runtime.

You can also write "Some Words".to_owned() for example to the same effect.