Cloned objects are replicated physically rather than logically to secondary databases. That is, cloned tables in a standard database do not contribute to the overall data storage unless or until DML operations on the clone add to or modify existing data. However, when a cloned table is replicated to a secondary database, the physical data is also replicated, increasing the data storage usage for your account.
https://docs.snowflake.com/en/user-guide/database-replication-considerations.html#:~:text=Replication%20and%20Cloning,-Cloned%20objects%20are&text=However%2C%20when%20a%20cloned%20table,storage%20usage%20for%20your%20account.

Column-level security in Snowflake enhances data protection by restricting access and applying masking policies to sensitive data at the column level.
Limiting Access Based on User Privileges:
Column-level security allows administrators to define which users or roles have access to specific columns within a table.
This ensures that sensitive data is only accessible to authorized personnel, thereby reducing the risk of data breaches.
Application of Masking Policies:
Masking policies can be applied to columns to obfuscate sensitive data.
For example, credit card numbers can be masked to show only the last four digits, protecting the full number from being exposed.
Reference:
Snowflake Documentation: Column-Level Security
Snowflake Documentation: Dynamic Data Masking

A Stream object in Snowflake is used for change data capture (CDC), which records data manipulation language (DML) changes made to tables, including inserts, updates, and deletes3.

The WAIT_FOR_COMPLETION = TRUE parameter in an ALTER WAREHOUSE command ensures that the command does not return until the warehouse has completed resizing. This means that the command will wait until all the necessary compute resources have been provisioned and the warehouse size has been changed. References: [COF-C02] SnowPro Core Certification Exam Study Guide