Thanks for the message!
I didn't know that angular offers something to facilitate the "bridge" (I was aware that it's possible to do it for React component as well), but the premise is still not wrong: if someone publishes a library of components *for Angular*, it's not directly availabe for everyone. Sure, an end user can wrap it using that technology, but (1) it's work to do and (2) it's less nice to have all these layers of wrapping, compared to directly building web components.
However, it's still good to know that there are solutions to embed a library with one framework into another, I would say, as a last resort :)