Why is this the answer?

The answer is coin because this clever riddle uses fun secrets to describe a simple piece of money that everyone knows. A coin is a small, round object that we use to buy things we need and want, like toys, snacks, and school supplies. We can figure out the answer by looking at each of the clever clues, like solving a mystery with a treasure map. The first clue says, "I am two-faced but bear only one." This clue is talking about the two sides of the coin, which are called "heads" and "tails." If you pick up any coin and flip it over, you will see that each side has a different picture or design. These are its two different "faces." But even though it has two faces, it is still only one single, round piece of metal with one value. The next part of the riddle is, "I have no legs but travel widely." Coins are always on the move! You might use a coin to buy an ice cream, and then the person at the ice cream shop uses that same coin to pay for something else. That coin is constantly traveling from one person to another, and one place to the next, like a busy messenger. It is always on a long journey, even though it doesn't have any feet or legs to walk with. The clue, "Kings leave their imprint on me," is about the pictures stamped on the metal. For many hundreds of years, coins have been decorated with the faces or special symbols of kings, queens, presidents, or other important leaders. That picture is the ruler's special "imprint" that they leave behind. The riddle also mentions that people fight over money. "Men spill much blood over me" means people sometimes fight wars or work incredibly hard to earn or keep money, showing how important it is. Finally, the last part is about power and being locked away. A coin has the "greatest power when given away," which means it works best when you spend it to buy a treat or help someone else. You use its power to make something good happen. But if someone loves money too much (that is "lust"), they will hide their coins away in a locked safe or a secret box and never use them. That greed keeps the coin "locked away," and it cannot help anyone, which is the secret of the last line.