Presta also is less vulnerable to valve stem cuts from the rim. Since they connect at the tube rather then have a sleeve of rubber running all the way to the top of the valve, the motion caused by using a hand pump (sawing the wheel back and forth) doesn't cut the stem and ruin the tube.

For a similar reason, using them on low pressure mountain bike tires makes sense too. At low pressures the tire can creep around the wheel dragging the valve stem up against the rim. A schrader can be cut and be ruined while a presta won't. A metal stemmed scrader doesn't have this problem but those are pretty rare.