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.
References:
* Snowflake Documentation: Column-Level Security
* Snowflake Documentation: Dynamic Data Masking

Explanation
You can experiment the same with snowflake UI.

* The VARIANT data type in Snowflake is used for semi-structured data such as JSON, Avro, or Parquet.
* A 16 MB size limit applies to an individual column when storing VARIANT data in a table.
* This size restriction ensures efficient storage and processing of semi-structured data.
References:
* Snowflake Documentation: VARIANT Data Type
* Snowflake Table Storage Limitations

Parquet is a columnar storage file format that is optimized for performance in Snowflake. It is designed to be efficient for both storage and query performance, particularly for complex queries on large datasets. Parquet files support efficient compression and encoding schemes, which can lead to significant savings in storage and speed in query processing, making it the most performant file format for loading data into Snowflake.
Reference:
[COF-C02] SnowPro Core Certification Exam Study Guide
Snowflake Documentation on Data Loading1