One answer is the strong compatibility story for existing JavaScript libraries. You can use d3 or three.js from TypeScript; that's a big advantage over somethin

One answer is the strong compatibility story for existing JavaScript libraries. You can use d3 or three.js from TypeScript; that's a big advantage over something like Elm. Compatibility with JavaScript source (instead of libraries) is a disadvantage. The most dangerous parts of TypeScript are the JavaScript parts: arithmetic, bracket notation, etc.