well
1. albums contain photocards and from what I know of kpop they are the most highly sort after item within an album - NFTs not so much unless there are NFT photocards which I'm not aware of
2. albums are tracked (for the most part) and selling more is a sign of success and bragging rights for success stans - NFTs not so much - I've never seen a kpop fan go wow my favs sold over 1m NFTs compared to wow my favs sold over a million albums...