For example, if you trade 1 bitcoin for another bitcoin, you are trading one identical thing for another. There is no loss of value on either side of the transaction — you both end up with 1 bitcoin. But if you trade 1 NFT for another NFT, they can be drastically different even if they appear to be the same. This is because an NFT includes a deeper layer of characteristics that make it different from others. These characteristics can include metadata, visuals, serial numbers, etc., and can all affect the value of the NFT based on what characteristics are valued by the people who buy and sell them.