Hey Docs,
I want to hear your opinions on this topic. They seem to be a very good core-stabilization exercise, and it really reinforces good posture and the purpose of the core as a stabilizer.
You also have a few variables you can change to either go for more conditioning or more static strengthening of the abs/low back. Distance, weight, rest periods etc. They can also train grip strength.
I only see benefits to be honest, but I rarely see people doing them. I was planning on doing them with moderately heavy dumbbells/plates and walk 30 seconds x 3 sets after my deadlift workout, once a week.