Been seeing a lot of comments about not journaling external scratch disks, but no one ever states why. From what I've read, journaling helps in the event of failure like a of power loss, which seems more likely for an external hard drive. Is it that the journaling slows down performance or is it something else that no one is stating?

I have six external enclosures all probably journaled used as scratch disks and back-up.

Years ago when Mac OSX introduced journaling there were some issues with stability and OS overhead causing hangs; that's a thing of the past. Today there's no reason not to use journaling and that's the default OSX configuration. It absolutely *will* and does help rebuilding corrupted directories, just ask the guys at Alsoft who make DiskWarrior.

Wholeheartedly agree. The "don't journal media drives" advice is outdated.

for the clarification. It's so commonly stated that it's probably passed on without even knowing why or why not.