I saw this thread earlier, and was ambivalent about it at the time.
But Yesterday, a guy worked our creek solo for at least 12 hours using an autodipper and clams for bait. All the while maneuvering a roughly 30 foot boat up and down his lines. The harvest at the end of the day was substantial, (though I didn't get close enough to ask).
I think the device allowed him to work the water much longer than he normally would be able to on a given day, and that reinforces the "effort" argument above.
I don't know the impact on the crab population in our creek though. I wish I could see through the water!