I agree wholeheartedly. jEdit, for instance, has the command "Expand Folds With Level", which does what I believe you are describing. After assigning a simple keyboard sequence (in my case, Alt + Enter) to that command, I can enter that sequence followed by a level number (1 through 9), and it collapses all of the lines below that level, which is great for quickly seeing the structure of the code at various levels of granularity. Even Microsoft Word has the same functionality (but of course not for lines of code but rather section headings of different levels and the text among them).
jEdit also has the commands Go to Next Fold, Go to Parent Fold, and Go to Previous Fold, making it easy to jump from one fold to another. I assume it's not the only application that has that functionality.
The screenshot you provided is from what application?