I guess it's almost like speaking two different languages when talking about what a DB guarantees and what your application REQUIRES in the form of guarantees. Typically, in my experience, they're not the same thing. Or not ALWAYS the same thing. Within the problem space you're trying to come up with a solution for, I'd say it's highly unlikely "ACID" guarantees are sufficient to say categorically (with 100% accuracy) that "my application is perfect because: ACID".