This article really doesn't say anything to make me think this "component" nonsense is worth much.
Like the non-semantic gibberish "custom elements" trash, that since the UA has NO clue what any custom tags mean, they completely miss the POINT of HTML and amount to nothing more than glorified DIV. They provide zero improvement in accessibility, usability, and just reek of the people who sleaze endless pointless idiotic DIV for nothing and hordes of incompetent presentational classes jonesing for a different way of using the same broken HTML 3.2 mindset!
Just more proof the WhatWG wasn't qualified to create 4 Strict's successor -- alongside the now deprecated HGROUP, acceptance of EMBED, SECTION resetting to H1 depth, and other such idiocy.
Same for the shadow DOM, everything I've seen done with it either being stuff existing fragments already accomplish, or garbage that has zero business having client-side scripting involved in the first place.
This whole "encapsulation" nonsense just being a result of people not embracing semantic markup, separation of concerns, leveraging selectors and using classes/id's to group or identify, not blatantly declare style. They jump through all these ridiculous nonsensical hoops because "wah wah, eye dunz wunna lurns two use teh HTML un CSS properly"
It all just reeks of "WET" developers trying to take the simplest of tasks, make them as hard as possible to implement, whilst flipping the bird at the very reason HTML and CSS even exist!
I would probably have helped a lot more if you'd shown real examples of this in action, something that seems to be missing from most every article, page, and site on the topic.