In what scenario are programs like this useful?

Question

let newArr = ['Three', 'Four'];
let arr = ['One', 'Two', ...newArr, 'Five'];
console.log(arr);

Answer 1

Infinite situations, like you made a list of usernames but you want someusers shown not at the last but between of other array values.

Answer 2

Also useful for asking questions in Q&A.