[realharo]

>map because they think it's more readable and productive without any great way of proving that that's true?

I mean, doing

    sendUserIds(users.map(u => u.id))

is very obviously more readable than what you're forced to do in languages like Go

    ids := make([]int, len(users))
    for i, user := range users {
        ids[i] = user.Id
    }
    sendUserIds(ids)

The difference only grows once you start needing to do more operations, grouping, putting stuff into map by a certain key, etc. Many languages also have lazy sequences for such operations (e.g. https://kotlinlang.org/docs/reference/sequences.html, though they aren't always faster, it depends)

The code in the comment above is however not an example of this, and is actually less readable in my opinion. It seems more like an author wishing to be using a different language instead of accepting what they have in front of them.