TypeScript does NOT shim async functions[1] for you, or give you fetch-api[2]? AFAIK, if you want that functionality, you still need babel and the fills/transforms to support async in browsers without it are freakishly huge payloads. That doesn't count dynamic imports and a number of other features that TypeScript doesn't support.

I'd rather not support a dead browser, that's been dead for years now, that has clear replacements and alternatives. Not to mention security concerns above and beyond development pain..

    [1] https://caniuse.com/#feat=async-functions
    [2] https://caniuse.com/#feat=fetch