Web Vitals give you a simplified way in how your app is performing. Collecting how your app behaves in actual devices gives you real and actionable insights.
Loaders and actions impacts directly how your app performs. Users dislike when page takes a long time to load or to respond to an action. A slow loader or action response time can be responsible for inferior user experience.
As loader and actions calls gives you how your app behaves as a whole, recognizing which routes are causing most of the problems that prevent to deliver a delightful experience to your users.