It is good that they are continuing developing a decent alternative to MS Office but I would rather they spent time on improving the MS Office compatibility than adding in functions for 1% of users.
The redaction tool is something you could achieve the same result with the older versions of Libreoffice with just a couple more steps. Just tried it with Libreoffice 5.1. Export your document as a PDF, open the PDF in Draw, paste shapes over the words you want to redact, select all and convert to bitmap from the tools menu and save it.