I started doing that last year and it worked good for me to a one hook rig.I have seen posts several times by Ralph Smith that he uses a single hook harness with just a small piece of night crawler.
I tie my own harnesses, and use three hooks. I use a treble for the bottom hook. When I fished last weekend, I forgot to bring my spool of extra harnesses. Half way through the afternoon, a big catfish broke off the bottom of one of my rigs. I was left with just a single hook on it. I decided to use Ralph's advice, and sent it back out with just a "piece" of crawler on it.
I really didn't expect it to work very well; BUT, that rig outperformed the rest of my harnesses.
I'm not sure why I'm reluctant to switch over to a single hook harness still (with just a piece of crawler instead of a whole one). But I AM going to make up some singles and see if it continues to work.
Thanks for the tip Ralph!