Answer:
I am easy to waste. I am unstoppable. What am I?
I am the signature stroll of ducks and penguins
lighter than feather and softer than silk yet the strongest man in the world cannot hold me for more than a few minutes.
I dig out tiny caves and store gold and silver in them. I also build bridges of silver and make crowns of gold. Sooner or later everybody needs my help yet many people are afraid to let me help them.
I am full of holes but still hold water. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.