Security defaults are a set of pre-configured security settings and features provided by Microsoft to help protect your organization’s data and resources. They are important for several reasons: 

Instant Protection: Security defaults offer a quick and easy way to enable essential security measures, helping you establish a baseline level of protection for your Microsoft 365 environment without the need for complex configurations.

Defence Against Common Threats: These settings are specifically designed to guard against common cyber threats like password attacks, unauthorized access, and phishing. By enabling security defaults, you’re reducing the risk of these threats compromising your data.

Continuous Updates: Microsoft regularly updates security defaults to adapt to new threats and vulnerabilities, ensuring that your security measures stay current and effective. 

Compliance Alignment: Enabling security defaults can help you align with various compliance standards, such as those required in specific industries or by data protection regulations like GDPR.