This EWI is related to the Transact USE statement transformation. By default, the statement is not going to be transformed, the user has to add the explicit parameter in case he wants the statement to be migrated to the Snowflake equivalent.
USE [MY DATABASE]
-- ** MSC-WARNING - MSCEWI4001 - Transformation for USE <database> is disabled by default. **--USE "MY DATABASE"
usedatabase parameter in the conversion tool in order to migrate the statement.