Is Dart a particularly optimised language for front-end development?

Hi. I remember when Dart was introduced, it was supposed to be a "JavaScript alternative" (?) for browsers.

It however "evolved" into being almost only used in Flutter, for developing mobile, web, and desktop front-end development.

It seems bizarre to me that a language is so special-purpose for front-end. Even Ruby has some fringe use cases beyond Rails.

Does Dart have any particular features that justify such a decision to bind Flutter to it? Or it has all been accidental?

Thanks