Difference between Promise returned with or without keyword 'new'

They both seemed to work, but what is the difference between:

return await new Promise.all([p1, p2])
                .then(value => console.log(value))

return await Promise.all([p1, p2])
                .then(value => console.log(value))

Especially if I am going to be calling the promise function within a cron job? Will one take up more resources than another? Eventually to having to set

const EventEmitter = require('events').EventEmitter;
const emitter = new EventEmitter();

Strange, in this babel repl, I get

TypeError: Promise.all is not a constructor

in console

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