The article isn't resolving, so I can't speak to what it exactly says.

However, the question isn't "on your own domain vs not," it's "how you publish." Blog networks are popular because most people do not have the technical ability to spin up a server, buy a domain, and point it at it.

Why an atproto based solution instead of Medium or whatever? Because then you actually own your own data. And that also doesn't preclude it ending up on your own domain in the end anyway, because it's your data.