Easy to debug
When you develop with webcomponent, you work with chrome devtools instead of library dependent devtools. And chrome devtools has the best performance.
Bundle size matters
Hello world react, vue, lit project bundled size is 143.39k for react, 52.88k for vue, 20.88k for lit. Lit is smallest of all. Btw, vue is small compared to react, since it's using tree shaking.
Native browser component
webcomponent is browser native. It means library that you wrote never go out of date.