Why are table valued parameters to SQL Server stored procedures required to be input READONLY?

Question

Can anyone explain the design decision behind preventing table valued parameters from being specified as output parameters to stored procedures?

I can\'t count the n

Answer 1

Still in 2020, SQL version "Microsoft SQL Azure (RTM) - 12.0.2000.8", I am not able to edit the Table value parameter within the Stored Procedure. So I did the work around by moving the data into Temp table and edited it.

ALTER PROCEDURE [dbo].[SP_APPLY_CHANGESET_MDTST09_MSG_LANG]
    @CHANGESET AS [dbo].[MDTSTYPE09_MSG_LANG] READONLY
AS
BEGIN

    SELECT * INTO #TCHANGESET FROM @CHANGESET 

    UPDATE #TCHANGESET SET DTST08_MSG_K = 0 WHERE ....
     ...............