It is not absolutely necessary to specify SNAPSHOT isolation for simple INSERT/UPDATE/DELETE operations. However, if a table has complex triggers or a stored procedure is executed instead of a simple /UPDATE/DELETE query, it is advisable to use SNAPSHOT. The reason is that READ COMMITTED isolation does not ensure the read consistency of the statement within one transaction, since the statement in this isolation can return data that were committed to the database after the transaction began. In principle, SNAPSHOT isolation is recommended for short-running transactions.