Cave Holes appear in the Caves. There are treasures in each Cave Hole. They can not be picked directly. Using The Lazy Forager is the only way to pick them up. The treasures in Cave Holes will respawn when the Ruins Regenerate.
The Lazy Forager is often considered as a relatively expensive item to create therefore it may be situational as to whether a player wishes to create one to be able to collect the item.