Here's why:
* Greed and Untrustworthiness: Goblins are known for their greed and are often seen as untrustworthy. They prioritize their own interests, making them unreliable protectors of valuables.
* Gringotts Wizarding Bank: While Gringotts is the most secure bank in the wizarding world, it is run by goblins and is often targeted by criminals like Voldemort. This highlights the fact that goblins are not necessarily ideal guardians due to their potential for greed and vulnerability to manipulation.
* Magical Abilities: Goblins have magical abilities, but they are not necessarily focused on protection or defense. Their magic is often used for more practical purposes, like crafting or manipulation.
* Other Guardians: There are other, more suitable options for guarding valuables in the wizarding world. For example, enchanted creatures or powerful wizards are often employed for this purpose.
In the Harry Potter universe, goblins are often associated with money and banking, not security. They are skilled artisans and work with magical materials, but their reputation for greed and untrustworthiness makes them unsuitable as guardians.