Immediately after switching the page, it will work with CSR.
Please reload your browser to see how it works.
Normally the use case is that you still want to distribute it as a PDF, usually consisting of many pages, and without loss of quality, so the printing/scanning/screenshotting option may not be very practical.
No, the real solution is to use an editor that allows you to remove text (and/or cut out bitmaps), before you add black rectangles for clarity.