Collaborator Codes aren't just for two multiple people- you can also utilize them for working on multiple devices!
The account you create the site on will always be the owner of the site. Do you have multiple Apple IDs? Or different devices? Want to work from the Web App?
Invite your other accounts to edit your site from any device!
In regards to subscriptions, domains and deleting the site, you will still need to contact Support from the Owner account. Member accounts cannot!
More information about Shared Sites can be found here.