There is no distinction in Phlex. The distinction is only made in generated code in Phlex-Rails where it felt like a sensible way to fit with the existing mental model. Views are technically just components, but they are expected to be HTML documents composed of components and rendered directly from controller actions. You wouldn’t want to render a view inside another component because you’d get another doctype and `<html>` tag. So they are sort of “entry points”.
> There's a little metaprogramming in SGML::Elements I dislike
Many crimes are committed in the name of performance. For example, we have a different code path for standard elements with attributes and content, standard elements with attributes but no content, standard elements with content but no attributes and standard elements with no attributes or content. Not to mention void elements.
This allows us to reduce the number of string concatenation operations required during rendering and is why it renders ~1.5gbps of HTML per core.
I’ve considered having an API-compatible minimal version of Phlex that would be much easier to take on and maintain yourself if it didn’t make all these performance optimisations.