Take a look at this[0] with regards to strings.

I'm not really sure why you'd use new String anyway - it won't always act as a string primitive. Rather than making Symbol reimplement the same quirks that other built in constructors do, isn't not allowing a Symbol constructor going to avoid a lot of confusion?

For example, if you created an object using a hypothetical symbol constructor, the symbol would be converted to a string if you tried to use it as an object key (internally, JavaScript sees your symbol object as an object, not a symbol), which is simply creating problems for a naive programmer.

[0] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...