It doesn’t matter if you have one of the many copies of the Bored Ape jpeg NFTs others have made, what matters is you have an NFT provided by contract 0xaba7161a7fb69c88e16ed9f455ce62b791ee4d03 . The jpeg is irrelevant even. If you have an NFT from this contract you are in the club.

If the jpeg is irrelevant, shouldn’t all NFTs from the same contract cost the same? If it’s just a club membership, why would people buy multiple NFTs from the same contract?

Broadly, because there are multiple tiers of status at play.

1) "I was rich enough to buy a Bored Ape NFT". This is for status relative to people outside the club.

2) "I was rich enough to buy a super-expensive Bored Ape NFT". This is for status within the club, it lets them all know how rich you are.

It's all yuck to me, but people have different motivations.

Onchain metadata, the ERC721Metadata standard allows key value pairs associated with the NFT, this is where well the hyperlink to the jpeg is stored. These further allow non-fungible properties to the individual token, and where the rarity is derived (eg: hat: red, which 5/10k tokens have).