Is it just that nvarchar
supports multibyte characters? If that is the case, is there really any point, other than storage concerns, to using varchars
I would say, it depends.
If you develop a desktop application, where the OS works in Unicode (like all current Windows systems) and language does natively support Unicode (default strings are Unicode, like in Java or C#), then go nvarchar.
If you develop a web application, where strings come in as UTF-8, and language is PHP, which still does not support Unicode natively (in versions 5.x), then varchar will probably be a better choice.