Core Web Vitals are not an abstract score: they are the time your page takes to become usable. Over threshold, Google penalises it and visitors leave.
LCP concerns main content loading, CLS visual stability, INP responsiveness to taps. The three are solved with optimised images, managed fonts and measured JavaScript.
The practical rule: every image over 200KB must be compressed, every third-party script deferred, every font preloaded.