And it isn't four lines saved, but four lines times the number of uses in the entire code base.
Why would you believe that?
And if you do believe that why don't you use a code golfing language?
Should someone now have to point out to you that a million-line function is worse than a ten-line function for calculating fizzbuzz? Is that meaningful discourse in your book?
In general I believe that number of lines of code is correlated with number of bugs, but I would hesitate to say that it is proportional to. Going in with the explicit goal of reducing the number of lines could easily lead to more bugs, not less.
Having less lines can make extremely unreadable code. Readable code with an error is easy to fix, unreadable code is not.
At the very least the ambiguity of doing TWO things (matching AND destructuring) should not be allowed since it changes the outcome based on whether a value is a literal or a variable with the exact same literal assigned to it (at least that's how I understand it from reading the examples)