They’re not suggesting you don’t store it… I don’t think you’re addressing the real concerns here. How I read the concerns: External connections to your data b

They’re not suggesting you don’t store it… I don’t think you’re addressing the real concerns here. How I read the concerns: External connections to your data belong in a field or a separate table to ensure that your data is not so tightly coupled to the key you’ve chosen that you limit your data model’s expressive power. Don’t make an external identifier the primary key in your database.