Externalized Strings

Is there any advantage if ever I use externalized strings? I was just wondering in what circumstances I could use it. Thanks.

Localisation.

Could you explain what localisation is? I really don't know.
Edit: Wait, is it the one used to provide the language versions on strings? Like for example, the Quest text and others?

If someone wanted to convert your map to another language, if all the strings are external, the person can just translate the file and import it back in. If you keep your text within the code, it's harder to do so.

I have gotten into a habit of externalizing internally. I make a global array of strings and initialize them in one place. Then as I need them, I just use the arrays. So if some person were to translate, they would only have to translate that section and they would be good to go.