sql server 2008 partitioning column

According to microsoft An Identity column cannot be a partitioning column canadate.

The partiti开发者_运维知识库oning column cannot be an identity, default or timestamp column.

They do not clarify why that is nor has my google foo turned up a reason.

I have a theory, can SqlServer not automatically insert the row into the correct shard based on the identity field if it is the partitioned column?

Your reference is for SQL Server 2000 and partitioned views.

SQL Server 2008 allows Identity fields as the partitioning column in a partitioned table.

See this link, excerpt below:

All data types are valid for use as partitioning columns, except text, ntext, image, xml, timestamp, varchar(max), nvarchar(max), varbinary(max), alias data types, or CLR user-defined data types.