Ark was not initially conceived as a channel factory, but it could be used for that purpose. The breakthrough of Ark is the ability to develop an architecture that we thought was only possible with covenants, but that is achievable with multisigs (and a lot of interactivity).

I'm studying Ark for a couple of weeks now and trying to explain it here: https://joaobordalo.com/labs/ark/

Still work in progress.