Hi,
Thanks for your support.
The description of the MailChimp plugin was a bit lacking. I've added information about that capability.
I've also worked on this today to add support for subscription during the registration process with a new setting in the plugin to select the subscription mode: on registration, on order, or both.
Please update to the 1.3.0 version of the plugin to get the extra option.
Also, note that the plugin relies on a custom field of the table "user" for the consent, not the table "address". The address table doesn't make sense since a user can have several addresses for his user account but you only want him to provide consent or not once.