Why is sandbox so popular?

In recent years, the blockchain and cryptocurrency space has witnessed a surge in popularity for Sandbox, a virtual world platform that enables users to create, own, and monetize their voxel-based assets. Could you elaborate on the key factors behind the immense popularity of Sandbox? What are the unique features or benefits that it offers that set it apart from other similar platforms? Additionally, how has the integration of non-fungible tokens (NFTs) and play-to-earn mechanics contributed to its widespread appeal? Lastly, could you discuss the potential implications and opportunities for investors and developers alike in this rapidly evolving ecosystem?