What is MetaMask used for?

Can you tell me more about the uses of MetaMask? I've heard it's a popular tool in the cryptocurrency world, but I'm not entirely sure what it does. I'm particularly interested in understanding how it helps users manage their digital assets and interact with decentralized applications. Is it primarily for storing cryptocurrencies, or does it have other functionalities as well? Also, what makes MetaMask a preferred choice among crypto enthusiasts?