Octopus hooks are versatile and popular hooks for many reasons (what else would you tie a mooching leader with?

). I like them for fly tying mostly for experimenting because they're cheap and usually "laying around" as you pointed out. The profile is also well suited to shrimp patterns.
Other than the upturned eye and offset point, Octopus hooks are a close match to many saltwater hooks. Including dedicated fly hooks like these Ahrex Bluewaters I just ordered. My evil plan is to hide these in the front-end of squid patterns roughly the length of a table knife.