A smart contract is the code that powers your NFT. It tells the blockchain that your NFT exists, is yours, and what is consists of.
On Foundation, each time you create a Collection, you are creating a new smart contract.
We make it as easy as possible for you to mint an NFT without having to worry about the technical specifics happening behind the scenes, but this does not mean that you should not care about your smart contract.
First, and most importantly of all, you want your smart contract to be owned by you. Some NFT marketplaces do not tell you that if you mint on their platform, the contract will be under their ownership. When the contract is yours, you can take your NFT anywhere you like.
On Foundation, you own your NFTs, period.