I don't think they're saying it's a bad idea in general, the issue here seems mostly related to the shadow dom making it difficult/complicated for people to the

I don't think they're saying it's a bad idea in general, the issue here seems mostly related to the shadow dom making it difficult/complicated for people to theme atom/re-use components etc... I'm not a web developer but I'm sure there are valid use cases for it, as well as use cases such as this one where it's not ideal