GDPR requires organizations to implement appropriate technical and organizational measures to ensure a level of security appropriate to the risk. CMK supports this requirement by enabling strong encryption practices, which are critical for protecting personal data against unauthorized access.  
Currently enforcing customers own encryption key is only available through application level which requires extensive implementation cost that will delay projects and cause customer frustration, when their other resources in Azure or data platforms like Snowflake support CMK out of the box. As part of an enhanced security add-on it would be great with such functionality at platform level.