Moto-Bunny, let me try to explain my point with another example.
I bought a pre-paid phone a few years ago. It was someting like 30 euro with 50 euro prepaid. That is, I paid less for the phone and paid calls than the value of the calls.
Few days later I wanted to buy a cover for the phone. It was 10 euro. What? Sorry, I'm not paying just for the plastic cover a third of what I paid for the phone+calls. I rather use the phone and buy another one with the price of three covers, and will get 50 euro more in phone calls.
Case guards are "cheap" insurance if they are cheap. If their price is close to what they protect, then there is no point in using them unless it is to avoid being stranded for a spilling alternator cover or bent points cover. Courier rides here use guards, they can't afford not to work one day for having to repair their bikes, but their bikes are workhorses and looks is secondary.
Sure thing, there are cheap case guards, but I bet they bent like spaguetti under the weight of a CB750, much more if the bike was in motion before the fall, and between damaging the frame or damaging an engine cover, I rather have the latter.
We are sending a message with everything we do. From what we say to what we write, what we wear, what we ride and how we ride it. People who wear a brain cap are also sending a message. They prefer to get the expected result of the image they send than get the protection of a full-face helmet. You say you don't care for what others think. If I would think that case guards are worth for me what they cost, I would use them without worries. As that is not the case I don't use them, and as I have seen many newbies taking their bikes out of the showroom with the case guards fitted for fear of damaging their new bikes, I don't like to be taken as one, is that simple. Not that I have anything against newbies, I have been one myself. We could go on and on on why some people think that wearing chaps looks gay, and we will have chap-wearing people saying they don't give a damn. You like chaps and think they offer protection, people tells you look gay with them, you don't give a damn and wear chaps, end of the story. The same goes with case guards.
I have a curious picture about case guards, as soon as I find it I will post it.