One thing that's unclear to me in how I might manage this "side-by-side coexistence": how you manage potential route conflicts, e.g., You have a Hologram "page" that defines `route "/hello-world"`, and the Phoenix application router.ex also defines a route, `live "/hello-world', MyApp.HellowWorld, :index`.
I could imagine the lack of a central router may be offset through conventions of how you organize pages (perhaps a directory-based-routing convention). I saw in the Installation section that it's common to organize under `app/`, and `app/pages`. Maybe an expansion on best practices for larger project organization, and how you keep Hologram routes straight, would be interesting to other people as well.
Regardless, I've just started dipping my toes in the elixir and phoenix ecosystem about 3 months ago, and it's been a real joy. I'm throwing every hobby project I can think of at it to learn more. I'll give hologram a spin -- thanks again for such clear documentation.