[DanitaBaires]

I took it more like the way you specify certain jQuery operations such as:

    $('.card').hide();

to mean "hide all cards", or

    $('.card.green').show();

to mean "show all green cards". It's really comfortable to think about operating on the set like this and not having to worry about looping on the individual items.

[buro9]

In fact thinking of it as a set frees computing to do things concurrently invisibly.

A lot of other comments here say "ah, but that's just JS iteration still"... but there's really nothing to prevent it being the equivalent of a Go routine... no order implied, no iteration implied, but all the things in the set will have the functions hide() or show() called.