Sure, just as you'd understand a library or function to be "thread safe" it could be considered "transactional." I'm saying STM is to be used in as fine a grain

Sure, just as you'd understand a library or function to be "thread safe" it could be considered "transactional." I'm saying STM is to be used in as fine a grain as possible, even if it's composing "larger grains." Just as thread-safety doesn't mean entering a shared, global critical section at the beginning of every function, STM doesn't mean that every block of code should be wrapped in a transaction. STM should really only be applied to writes that would cause the system to be in an improper state if partially applied.