

The screenshot folder itself is certainly not limited to just screenshots. Any file you can save can be kept in there. To my mind, the “entry point” is “saving a file to this particular folder”, regardless of the specific method used to do the saving. The screenshot is just an extremely convenient way to do that.
I just thought of a way to improve this technique with Tasker. Tasker can work with the clipboard, edit files, and take a screenshot. So, you could set up a gesture to trigger a task in Tasker. Tasker can then take the screenshot, dumping it into the folder. Tasker can then check the clipboard; if there is text in your clipboard, it can prepend it to a single “TODO.txt” in your screenshot folder.
Linux could be configured much the same way, using shutter and xclip to capture the screenshot and clipboard, respectively.




Let’s try this a different way…
How do you want to indicate something should be retained? What is the single, physical act you want to perform to tell the operating system “this thing needs to be captured”?