Promise.all() itself doesn't inherently cause unhandledRejection events. Any rejected promise that is left unhandled will throw an unhandledRejection, allSettled just collects all rejections, as well as fulfillments for you. There are still legitimate use cases for Promise.all, as there are ones for Promise.allSettled, Promise.race, Promise.any, etc. They each serve a different need.

Try it for yourself:

> node

> Promise.all([Promise.reject()])

> Promise.reject()

> Promise.allSettled([Promise.reject()])

Promise.allSettled never results in an unhandledRejection, because it never rejects under any circumstance.