Yeah maybe it could in theory but there is a reason why they choose an CMS like Ansible instead of a premade container out of an dockerfile. Like you said they offer a full stack out of the box but at Cloudron we already have most of the components (and 2 of the base apps) needed. The only thing we lack are bridges and bots so most likely just Dimension.
A possibility would be to use something like ansible-bender to create a docker image out of the cloudron base image but it still would be complicated and a lot of work. You could preconfigure the playbook to only install the components we need. Whats really interesting is that it does install all the stuff into one single directory.
Don't get me wrong, it seems like a cool project, but I think there are better options for us than to use their ansible roles.