The article doesn’t say much but I’m going to assume it’s just a spray that serves the same purpose as the plastic.

Cucumbers are individually wrapped because it extends their shelf life by retaining moisture where the skin doesn’t really.

I think these guys are saying that coating them with this oil does the same thing.

Apples are sprayed with a waxy coating to make them look shinier. Most people like shiny apples and have no idea that it’s artificial.

In summary, you’re not supposed to wash it off and if you did it’s probably not enough to contribute to fatbergs.