My comment on a point that keeps coming up in bitcoin articles - how hashing isn't "useful".
Security works like that. What's the use of having a large army, locks, bank guards, and so forth if people are angels? People aren't, so we are force to make security a part of our budgetary concern.
All the technology that makes bitcoin would be moot if nobody read secrets or steal coins. We could just use a global central database server and keep it at some United Nations building.