Why is it advantageous for leaves in the rain-forest to get rid of water quickly?

Question

Why is it advantageous for leaves in the rain-forest to get rid of water quickly?

Answer 1

It rains a lot in the rainforest, so if water pools up on the leaves nutrients can actually leech out of them.  So, in order to retain nutrients in heavy rain, some leaves have adapted drip-tips or drain-holes to allow the water to run-off or through.

Answer 2

To stop the creation of mold which would kill off the plants.