In terms of performance, why would a Developer prefer using UI Policies over Client Scripts?

Using UI Policies can lead to improved performance for end users because they offer a more efficient way to manage form behaviors and user interfaces without requiring as many client-side script executions. UI Policies are generally designed to manage visibility, mandatory status, and read-only attributes without the complexities involved in scripting. This can result in faster form loading times and smoother interactions.

When using UI Policies, the server can apply changes directly based on field values or conditions without needing to process each action through a client script. As such, because there's less scripting and fewer events that trigger processing, end users experience a more responsive and seamless interaction with the ServiceNow platform.

Client Scripts can introduce additional delays and server calls, potentially leading to increased load times, particularly if they rely on numerous or complex script executions. Thus, for scenarios aimed at optimizing user experience and application performance, UI Policies are often the preferred choice.