No, I'd consider them a standard and a candidate for implementing the case study. When I started the study I was thrown off by this: https://caniuse.com/?search=components - and very huge polyfills. In hindsight I'm not sure if I dismissed WC too quickly.

This is probably thin ice, especially since I've never built anything with WC, but they always seemed slightly over-engineered. I will try to learn about WC a bit more and maybe elaborate on my reasoning here.