Tracing is crucial for developers as it allows them to efficiently monitor errors across multiple services, reducing time spent on manual log digging and increasing productivity. PagerDuty's integration with Sentry enables tracing through unique identifiers, providing a clear picture of error impact and context. Alerts from PagerDuty incidents provide immediate visibility into errors, enabling teams to make calculated, proactive choices about next steps. The integration allows for customizable alert rules within Sentry, sending alerts to PagerDuty based on defined incident response workflows.