What is Visual Studio Code? Is it an efficient tool for Swift Development?
Visual Studio Code is a multi-language IDE and text editor, much like Atom.

Among it's strenghts there's it being highly modular, with plenty of plug-ins so you can build the best IDE for your specific needs.

It has gained quite a lot of traction within the StackExchange community, based on the latest survey.

While it's true that there are plenty of Swift plugins for VSCode, I have never used it for this purpose so far, although I enjoy working on it on other languages and as my generally go-to text editor.