Tomasz Tunguz, a partner at Redpoint Ventures, discusses the importance of customer success (CS) in SaaS startups, emphasizing its impact on growth and capital efficiency. He provides a hypothetical SaaS company's metrics to illustrate how CS can reduce churn and increase revenue, indicating a potential 50% revenue boost from a 2 percentage point decrease in churn. The analysis suggests that spending on CS can lead to a meaningful return on investment by enhancing customer retention.