sparse varchar columns

SQL Server 2012

The documentation suggests space savings on sparse varchar columns if you have more than 60% nulls.

This seems inline with varchar docs "storage size is the actual length of the data entered + 2 bytes"

However, when I run the following script, the results I see are that the tables are exactly the same size.  Is my test erroneous or am I missing something else?  Is there any benefit to having sparse varchar columns even when all rows are null?

Use Research

CREATE TABLE UnSparsed(
	ID INT IDENTITY(1,1),
	FirstCol varchar(100),
	SecondCol varchar(100),
	ThirdCol varchar(100),
	primary key clustered (ID) with fillfactor = 100
)
GO

CREATE TABLE Sparsed(
	ID INT IDENTITY(1,1),
	FirstCol varchar(100) SPARSE,
	SecondCol VARCHAR(100) SPARSE,
	ThirdCol varchar(100) SPARSE,
	primary key clustered (ID) with fillfactor = 100
)

GO

set nocount on 
DECLARE @idx INT = 0
WHILE @idx < 50000 BEGIN
	INSERT INTO UnSparsed VALUES (NULL,NULL, null)
	INSERT INTO Sparsed VALUES (NULL, NULL, null)	
	SET @idx+=1
END

set nocount off 
GO

sp_spaceused 'UnSparsed'
GO

sp_spaceused 'Sparsed'
GO

select * from sys.dm_db_index_physical_stats(db_id(), object_id('unsparsed'), null, null, 'detailed')
select * from sys.dm_db_index_physical_stats(db_id(), object_id('sparsed'), null, null, 'detailed')

DROP TABLE UnSparsed
GO

DROP TABLE Sparsed
GO