There's a lot of contradictions in this comment.

> it's self-contained: it brings along its own dependencies, whether that's JavaScript, templates, CSS

> Also, don't do this [...] That just adds HTML bloat to the page, something people with a singular focus on eliminating JavaScript often forget to worry about. To many HTML elements can slow the page to a crawl.

A static JS-less page can handle a lot of HTML elements - "HTML bloat" isn't really a thing unless those HTML elements come with performance-impacting behaviour. Which "self-contained" web-components "bringing along their own dependencies" absolutely will.

> shouldn't require an external framework

If you're "bringing along your own dependencies" & you don't have any external framework to manage those dependencies, you're effectively loading each component instance as a kind of "statically linked" entity, whereby those links are in-memory. That's going to bloat your page enormously in all but the simplest of applications.