Yeah, technically this is possible. Patreon WordPress will register users to your WP site if they log in via Patreon and they dont have a linked account before. So you can actually do that.
But i didnt test if disabling account registration in WP general options would prevent the plugin from generating user accounts. You may test after disabling account generation.
If it doesnt let the plugin to create user accounts, then you can just remove register/login links from your sidebar, widgets etc while leaving account creation option in WordPress on. This would cause your users to go through Patreon like a social login.
With 1.0.2, we are going to Connect with Patreon shortcode, which you can use to print out login buttons anywhere on your site. This update is to be released soon, so you can make use of that functionality to put buttons in your login pages or widgets.
