[8bithero]

Metaplex's Candy Machine) is the most widely used Solana Program for minting Solana NFTs [Note: Smart Contracts are called "Programs" in the Solana ecosystem].

Metaplex released Candy Machine V2, but Sugar seems to be a brand new rewrite of the program and the successor of CMv2 - However it seems it's still in beta. The CLI just lets you interact with the Solana BlockChain to register NFTs (Setup Mint Authority etc.)

The reason it's written in Rust is because Solana uses Rust. Similar to how Etherium Smart Contracts need to be written in Solidity, Solana Programs need to be written in Rust.

I know it's not the best explanation but I hope it helps clarify things at least a little.