If I am flying VFR, and have no noise abatement considerations, I always try to keep my circuit within gliding range of the airfield. I do this because I only have one engine, and if it stops and I am outside of gliding range, I am in big trouble.
I do not know many single engine aircraft that could glide to the runway from a 3 degree approach, so you better hope the undershoot is good. Why take the risk?
On the displaced threshold question, I note several postings do not consider the area before the threshold to be part of the runway. I assume in this case they do not use it for takeoff either? What do people do if there are no runway markers, this is the case on some unlicensed strips? If a displaced threshold is set for a 3 degree slope and you are coming in at 7 degrees, you know this is the case and have checked with the airfield operator and got his permission to use the undershoot in order to avoid an overshoot through the hedge, would you still not use it?
I put the following forward because the topic is much more complex than it at first appears. I do not normally land before a displaced threshold, but I have done it, quite deliberately, on a number of occasions.