Well, anything else than Finnish → Finnish. So it depends. And that’s why I think hiding it and using custom one instead when needed would be more helpful. But now in my reality I and my users are seeing an option that is practically never used.
Translations are really difficult question, because needs can be so different.
Before this change, the composer helper translated to your interface language (which was probably Finnish too) when you clicked “Translate to English”. I don’t think this was more helpful.
Maybe there could be an option to hide the default composer translate option when the user’s language and the site’s default language are the same.