I have a personal wiki instance hosted for that purpose. I collect knowlege in it, that I might need later and forget. Although I might not use dokuwiki, if I had so start the wiki again (would go to markdown).

How secure is the password protection?

That would chsnge nothing, simce they would also be on the hard drive.

Even when they are protected, when did they receive the last update? There are probably so much more vulnerable IoT devices.