Adopting a robust data governance policy in email marketing is crucial for various reasons. Firstly, it ensures compliance with regulatory requirements like GDPR, CAN-SPAM Act, and CCPA. Non-compliance can lead to heavy fines and legal consequences. Secondly, it enhances data security and protects against breaches, thus maintaining consumer trust. Lastly, good data governance improves data quality, which in turn boosts the effectiveness of email marketing campaigns.