Interesting indeed. Lol, when I started using computers, I never messed with settings. Mostly because I did not know how to. I've worked on many computers used by non-tech savvy people and those with Firefox browser installed never did any of the above.
:lol: It's a good thing for websites I've developed, I never relied on javascript and "fake it using images with CSS" tricks.
I've used three of those check boxes before, but always knew to change things back. Legitimately, I had a really bad connection and wasn't all too interested to see pretty pictures.
Override automatic cache management
I learned what this is about. A lot of webpage authors would teach how to get rid of cache... Instead of clearing cache every time a webpage would not load the way I expect them to, why not just permanently disable it? I then disable this to always get fresh content. This shouldn't be as harmful to do than it would've years ago. I do not know the ratio for people around the world who has good connection opposed to bad connection. Mines below average. For this to be brought up, I would imagine a good chunk of 98% of people has horrible connection.
To find someone who would actually do this wouldn't surprise me, I've seen a lot of dumb stuff people do with their computer. I have yet to witness this. To be fair, most people wouldn't touch this.
The entire certificate manager
This option is fairly buried in ADVANCED options, with techy-terms that should instinctively tell you that "you have no business here."