Data transformations during promotion from bronze to silver are used to clean and standardize the data, ensuring that it is ready for analysis and reporting. This includes tasks like removing duplicates, correcting data types, and filling in missing values.

Data transformations during promotion from bronze to silver are primarily aimed at aggregating and summarizing the data to provide a high-level overview, which might not preserve the granularity needed for detailed analysis.

The main goal of data transformations in this context is to denormalize the data to reduce the need for complex joins, thereby improving query performance, but this might not address data quality issues.

Data transformations during the promotion from bronze to silver are optional and not necessary, as the data in the bronze layer is already in a perfect format for any analytical processing.