Well, ya see, Bitcoin's blockchain wasn't really built to handle stuff like NFTs or other digital assets directly. It's mainly for transferring Bitcoin itself from one place to another.
But with OP_RETURN and some clever coding, people have figured out ways to represent other types of assets on the Bitcoin blockchain.
The thing is, this can take up a lot more space in the blocks - that's why some folks aren't too keen on it.
Remember though, mate: at the end of the day, it all comes down to how we use these tools responsibly!