Could BEGIN/END really be used inside CASE in SQL Server 2005?

The (still online) documentation for MS SQL Server 2005 states that BEGIN...END blocks can be used within CASE when it needs to execute a sequence of statements:

The BEGIN and END statements are used when [...] An element of a CASE function needs to include a block of statements.

...I'm unsure why it says that because CASE defines an expression which always yields a scalar value (including NULL) when evaluated; but BEGIN...END represents statements which do not yield a single value when evaluated.

...unless BEGIN...END could be used as a block preceding any value-yielding expression, but I couldn't find any mention of this in MSSQL 2005's documentation for CASE.

I no-longer maintain a SQL 2005 box in my homelab, my oldest is SQL Server 2016; and I tried a variety of possible T-SQL scripts that nested a BEGIN...END block within CASE within a SELECT but they all result in syntax errors complaining "Incorrect syntax near 'BEGIN'":

• With or without semicolons.
• With both types of CASE (CASE @x WHEN 1 THEN 2 ELSE 3 END and CASE WHEN @x = 1 THEN 2 ELSE 3 END).
• Using BEGIN...END for the WHEN clause.
• Using BEGIN...END for the THEN and ELSE clauses - including when THEN is elided.
• I also tried it in a SET statement (outside of a query), e.g.: SET @var = CASE WHEN ... END.

For example:

USE AdventureWorks;

SELECT
    c.*,
    CASE c.CultureID
        WHEN 'en' THEN 1
        WHEN 'es' THEN
            BEGIN
                DECLARE @y int = 2
                THEN @y
            END
        ELSE 3
    END AS caseWhen
FROM
    Production.Culture AS c;

If this really was never supported by SQL Server 2005 then was this perhaps a planned-feature which was documented before it was cancelled? It could also be the case (pun-unintended) that the technical-writer for this article was mistaken ( perhaps conflating the END in CASE END?); I'm just surprised that such a documentation error made it into the final release of SQL Server 2005 and still remains uncorrected for 20 years.

_{Because everyone is telling me to "just swallow your pride and try using AI more and you'll see that it really will save you time!" so I asked ChatGPT (free tier, if it matters) and it immediately confabulated nonsense about "the rarely used T-SQL CASE control-of-flow statement, which behaves similarly to IF…ELSE and allows BEGIN…END." - smh}