Maintaining confidentiality is essential for several reasons. Firstly, it complies with data protection regulations like the GDPR and CAN-SPAM Act, which can impose hefty fines for violations. Secondly, it helps in maintaining the trust and credibility of your brand. Subscribers are more likely to engage with your emails if they feel their personal information is secure. Lastly, it prevents potential data breaches, which can lead to financial and reputational damage.