We should not forget await

Quoting We should not forget the await (Exploring ECMASCript 2016-2017; 5.3.1 Don’t forget await)

[out value] is set to a Promise, which is usually not what you want in async functions. await can even make sense if an async function doesn’t return anything.

Source: Exploring ECMASCript 2016-2017, see-also (Returned Promises are not wrapped, Common Promise chaining mistakes, Tips for error handling)

Returning a promise from a promise, the engine will unpack and flatten it

Returning a promise from a promise, the engine will unpack and flatten it (Exploring ES6; 25. Promises for asynchronous programming)

Read more about async/await