What's the point of this lesson? JavaScript Course

Question

I'm now learning ES6 and I just finished learning how to destructure arrays and now I learn about object destructuring, however, in the lesson the second and third examples seem just pointless and stupid to me, this one for example:

let {a,b} = {a: 'Hello', b:' Jack'} ;
document.write( a+b );

Why would I ever do this, if I could simple do:

let [a,b] = ['Hello', ' Jack'];
document.write( a+b );

I understood the part which talks about how to define the object properties into variables, it's the other examples like the one I wrote above that seem unnecessary.

Here is the course link:
https://www.sololearn.com/learn/JavaScript/2977/

Answer 1

In realistic case you would most probably destructure an object returned by some function. Since it would be too long to introduce the function, you are given a short example, just to see what can be done and how.