What is Metaplex Core?

Can you tell me more about Metaplex Core? I'm curious about its purpose and functionality within the world of cryptocurrency and finance. Specifically, how does it enable creators and users to interact with blockchain-based platforms? And what kind of tools and services does it provide to facilitate these interactions? Is it a necessary component for building decentralized applications or is it more of an optional add-on? I'm eager to learn more about how Metaplex Core fits into the broader ecosystem of blockchain technology and finance.