Directory structure is largely an operating system term. It could be used for any sort of file system though, including websites. I can see how that domain could be used to branch off into SEO topics. Other than that, I'm not sure that options like OS directory structures are really going to work well for monetization. $11,000 is way too high, IMO. A maximum of $1xx is my appraisal. It's possible that someone would be willing to shell out a little more though, because it's a decent generic name.
As for the other domain, "cameras optics" doesn't do anything for me as a phrase. There are a lot of results on Google but most of them are just lists (i.e. "cameras, optics" or "cameras/optics"). This one, I can't appraise at over reg. fee.