Which is a valid choice, but it doesn’t mean that it isn’t successful or that it hasn’t taken off. Swift has achieved exactly the goal it was supposed to: become the official language for Apple platforms, replacing Objective-C as the entry point.

> If I need to write a CLI app, why, of all languages, would I pick Swift?

You probably wouldn’t. Other people might, for a variety of reasons including enjoying the language itself. I write CLI apps regularly and use several languages; Swift is one of them.