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).