Which one is better to use for actual product?

I’m wondering something about this post:


As a result of benchmark, the beginner solution is faster than the ES6 solution (I used this when solving the challenge) also the beginner solution is the fastest and the ES6 solution is the slowest.

When I read this post I am confused.
Which one is better to use when developing an actual product?
What is the important thing be faster or be shorter?

Challenge Link: