When I was taught the one thing that was drilled into me was the well-banked final turn.
In itself, a shallow turn is not dangerous, but add to that a low final turn and the risks start to build up. The natural reaction for a person is to raise the nose when low to get away from the hard bits, so to turn an inexperienced pilot might over-rudder to line up the nose.
If speed control is not right you have the stall/spin with no height available to recover
Again, since taking up power flying, I have been surprised to see how many pilots 'drag in' low down the approach from a long way out, relying on the donkey to keep going.
They should try a flight in a VW or 0-200 powered aircraft in an icing day - that would teach them a good lesson in positioning the circuit and height on approach