When using Synchronized Data Extensions, what consideration should be made for integrating data about cases from Service Cloud?

The consideration about moving to use the email address as the contact key simplifies the integration process significantly in this scenario. Email addresses are a common and unique identifier in both Service Cloud and Marketing Cloud, which makes it easier to match contacts between the two systems. By using email addresses as the contact key, you reduce the likelihood of data mismatches and can more seamlessly sync customer information related to cases from Service Cloud with the Marketing Cloud.

This approach also helps in maintaining a consistent view of customers, making sure that their interactions and cases logged in Service Cloud are accurately reflected in the Marketing Cloud environment. A uniform contact key across systems minimizes complications that arise from using different identifiers, leading to a more efficient integration process.