because in actually doing the exercise, and not just talking about it, you'd come up with your own tweak on the Todo app that couldn't be directly be in the training data. you, as a smart human, could come up with a creative feature for your Todo app to have, that no one else would make, showing that these things can compose between the things in their training data and produce a unique combination that didn't exist before. copying example-todo.app to my-todo.app isn't what's impressive, having it able to add features that aren't in the example app is what is. If it only has a box of Lego and can only build things from them, and can't invent new Lego blocks, there's still a large amount of things it can be told to build. That it can assemble those blocks together into a new model that isn't in the instruction manual might not be the most surprising thing in the world, but when that's what most software development is, is the fact that it can't invent new blocks really going to hold it back that much?