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
Since SQL Server 2019 varchar columns support UTF-8 encoding.
Thus, from now on, the difference is size.
In a database system that translates to difference in speed.
Less size = Less IO + Less Memory = More speed in general. Read the article above for the numbers.
Unless you have a very specific use-case go for varchar in UTF8 from now on!