That's all the files and subdirectories, and multiple levels of subdirectories, shown _at the same time_. Without needing to navigate in and out of directories.
If there's a way to do this using ncdu, then I've failed to find it. Screenshot please.
While you're going bananas on the pros of flame graphs, a significant con is that most of the names are unreadable. In your example, the legible information is not much more than what 'du -skh linux-4.9-rc5/*' would give you.
You can click to zoom, but in the default output I wouldn't call it a significant con anyway. It's usually (not always) an advantage.
Take that ncdu output above: "/drivers" is visible in the flame graph, whereas "/virt" is not. It's only printing the names of the largest rectangles -- the ones you care about, helping draw your attention to where it should be drawn.
That's all the files and subdirectories, and multiple levels of subdirectories, shown _at the same time_. Without needing to navigate in and out of directories.
If there's a way to do this using ncdu, then I've failed to find it. Screenshot please.