1. It does not address every other protected class under which an employer can be sued for discrimination (e.g., race, religion, color, national origin, sex [including pregnancy], military status, age, marital status, sexual orientation, gender expression or identity, genetic information, disability or any other personal characteristics considered to be a protected class under applicable federal, state or local laws)
Updating the policy matters because when sued for discrimination by a different protected class, you will be able to explain that everyone is protected in the workplace.
2. It does not list potential remedial measures (e.g., termination, suspension, probation, demotion, reassignment, etc.).
Updating the policy matters because employees who do not know the consequences are unlikely to care about changing behavior and, more importantly, without clear expectations an employer can be sued for arbitrarily applying their policy in a discriminatory manner.
3. It does not cause an employee to agree to its terms and to acknowledge written receipt of the policy and complaint form, which is required by law.