You are right. I was mistakenly thinking that the alternative (naive approach) would be to write the promise-creating tasks within the for loop, but if they are not part of the loop, the functionality is basically equivalent to Promise.all.

  // A -- Async and parallel
  const results = await Promise.all(data.map((i) => delay(i)));

  // B -- Functionally equivalent to the above
  const promises = data.map((i) => delay(i));
  const result = [];
  for (let a of promises) {
    const r = await a;
    result.push(r);
  }

  // C -- Problematic and naive approach: much slower
  const result = [];
  for (let i of data) {
    const r = await delay(i);
    result.push(r);
  }