There are a ton of reasons to buy these items/NFTs.
Unique - Each NFT is unique, it's only one of its kind. You cannot make another NFT that has the same token number on the same smart contract. Meaning that there will only ever be one of that token. This is verifiable by the blockchain and can be seen by anyone on the ledger.
2. Copyrights - Your NFT might come with the copyrights to the asset if the seller chooses to transfer them. The buyer of a token with copyrights transferred will be free to replicate or use it for commercial purposes. However, the NFT seller may set some conditions of use in the NFT description or metadata.
3. Rare - Since they are unique and cannot be copied, they are rare. Most of the time, artists release NFTs in limited quantities - it’s not often that they would mint 1000s of NFTs. Therefore, you can safely assume you would be one of the few people in the world that owns a collectible item, and that it is rare enough to give resale benefits.
4. Collectible - These NFTs/items are collectibles. Collectibles are valuable because they are rare, and they usually appreciate in value because quantities cannot be diluted. Buying them to resell them can earn you significant amounts of money - there are plenty of people who do it on a daily basis and make a living out of flipping NFTs.
5. Downloadable Files - NFT creators can include bonus downloadable files that only the current owner of the NFT can download, making it unlockable to the owner. If your NFT contains game assets, music, a PDF, or more locked inside it, you might want to buy the NFT just to download that song/PDF/etc.
6. Immutable - No one can change the metadata on the token, no one can remove the image or edit the name of the token, etc. This means it will never change, it will never be removed, it cannot be taken down off the blockchain. This is what gives it so much value and collectibility.
7. Forever - NFTs are forever. As the data doesn't change and it exists on the blockchain forever, you will always have that token. You can always resell that token if you want. It's like buying a bar of gold - you own it, and you can do with it what you want.
8. Resellable - You can always resell your NFT. You SHOULD resell your NFT and trade it. You can make some serious cash trading NFTs. Some NFTs have gone for 20,000 USD + when the original buyer only bought it for a few thousand dollars. Making them over 15,000 USD in a short time in ONE trade!