1) Supermetrics enables building a marketing data warehouse in Google BigQuery to store and analyze marketing data from multiple sources in a unified location. 2) This allows for cross-channel analysis and reporting on metrics and dimensions from different marketing platforms over time to help identify insights, trends and make informed decisions. 3) Supermetrics provides a simple process to set up the data warehouse without coding - connectors are activated within BigQuery, data flows are automated, and reporting can be done in Google Data Studio.