Thats one reason that its tempting to use something as simple as left pad. I only spend a small percentage of my time doing JavaScript, and the language has enough gotchas. Using something like that would give me the peace of mind that I haven't missed some quirk of the language. If someone knows how to publish a package on npm, then they probably know more JavaScript than me.
The point is that in the second case some people have no clue what's really happening, others have rough idea and very small group of people know what exactly happens. It might appear simple but it's not. It's easy.