You can tell who minted it. So the "uniqueness" comes from the fact that the original artist minted the NFT and the timestamp tells you if this was the first and/or only one minted by this artist for this URL.
The point is, there's no scarcity built in to an NFT. Scarcity builds far more value than a position in line.
Personal Opinion: By selling NFTs - metadata about the art and not the art itself - their integrity as an artist is already somewhat suspect in my mind.