Samuel Sieb:
The journal has nothing to do with memory management. It's about filesystem protection. btrfs would also be better because it is always "journaled" (not exactly, but fairly equivalent).
Bill Cunningham:
I thought it was involved in "swapping". Like a swap file my bad.
File system journalling is about all writing to a drive being done as a sequence (this write, then that update, then the next update). During a crash, hopefully you only lost the last bit of writing, and what was done before that is still there.