The practice of flying a continuous descent during a non-precision approach is in order to prevent approach and landing accidents resulting from destabilised approaches.
Fine in a piston or light turbo-prop twin to level at MDA plus a smidge but jet-ops normally demand that the aeroplane is fully configured, speed and flight path stable with landing checks complete by 500' A.R.T.E.
Having waffled on about the above how do we explain circling approaches and what about contingencies for engine failure during level segments with full flap, gear down etc