Когда используют .attr()?

Немного запутался с этой функцией, когда же используют всё таки attr()?

Его используют когда нужно создать новый атрибут, или же для динамического формирования значений атрибутов, вот пример когда массово задаются атрибуты тегу img:




<div
class="first">Достаю значение атрибута alt
<div
class="second">Достаю значение атрибута title

$("img").attr({
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title: "I am title",
alt: "I am your logo name"
});
$(".first").text($("img").attr("alt"));
$(".second").text($("img").attr("title"));

Или же вот так можно массово задать источник изображений по title:

$("img").attr("src", function() {
return "/images/" this.title;
});