[digitailor]

Interface: A point where two systems, subjects, organizations, etc., meet and interact. -(First Google definition, and the one that I was taught)

I think the author is confused. He isn't talking about interfaces, he's talking about functionality. In his examples of mobile applications, interface is actually everything: the app is a point of overlap between the user's singular need and the tool that provides a targeted solution. (We can argue over the distinction of user interface vs. interface, but I posit the former follows the latter.)

In other words, the mobile app interface is not non-existent, but perfect: a single point of overlap between need and function.

From the article: That’s precisely what a tool is: something which requires very little explanation for how to use it, because it is designed so precisely for its purpose, that how to use it is obvious. If you’re trying to dig a hole with your hands, you don’t need much explanation for how to use a shovel. “This is the handle” is about the extent of it.

That's an example of a perfect interface, not no interface!