Glad to see another DB fan join in here. Welcome!
I'm also glad to join the forum.
What I meant by comfortable is, for example, when you have an html list of rows and you need to build a link to delete the row. It is easier to use a link like 'delete?id=123' than passing those three keys all around.
But, as I said, it's really more about the application design / convenience, rather than a database structure.