Rich - More generally, the rule offers a playing option that will be invoked most often in match play when you are up a couple of strokes on a hole.
For that reason the rule will accentuate different strategies in match v. medal play. Most all rule changes over the last 100 years or so have gone in the opposite direction, aligning match and medal play more closely. So this is a small, but refreshing change in direction. Which is great.
In that vein, a possible scenario most likely to occur in match play:
Player up big on a hole is in a bunker facing a pin up against a water hazard. If he can drop outside the bunker with grass under his ball, he can spin it more reliably and minimize the possibility of his less predictable sand shot rolling out into the water. Even if his bunker recovery stays on the green, a shot off grass will increase his chances of leaving a shorter putt.