I'd be glad if someone could enlighten me on why the whole file needs to be encrypted. What issues does storing an encrypted value (password, metadata, etc) as

I'd be glad if someone could enlighten me on why the whole file needs to be encrypted. What issues does storing an encrypted value (password, metadata, etc) associated with a particular key (let's say website name) have? (apart from leaking the fact that that file has a entry associated with that site)