What are the use cases for the different "Recipient Type" options in CoPilot ?

Ian, they are very similar. The main difference is that based on selection from 2 to 4, it filters the columns in whichever object you have selected to be a contact, or email or user. 

For user, there is one additional delta if you are embedding reports in your email template. In the case where you are sending reports to internal users, you have the option of not filtering the report by account (since for contact or email strategy we absolutely want to make sure that one customer does not receive another customers data). 

In near future we will be adding some more details and making this strategy more prominent
1) Contact strategy will enable you to upload a CSV to filter contact instead of specifying criteria
2) User strategy will enable to just select users directly from your internal Salesforce table, without having to first select options. 

Hope that is helpful and happy to discuss more when we meet in person.

Thanks,
Gaurav

Hi Ian,  To define a Power List you ultimately need to get down to some set if email addresses.  You typically have some situation in mind like 'open support cases' or 'accounts nearing renewal' or something so you put a condition on Account or Case or whatever.  But then, you need to go further to specify 'who at the account' or 'who associated with the case' should actually get the email.  The simplest scenario is (1), which is basically saying 'everybody'.  All Contacts at an Account.  More often, you select which Contacts (2), such as the Contact with Role=Admin or the Contact who filed the case.   Now, if you want the email to go to the CSM on the account or the person who owns the Case, these aren't Contacts at all but rather Users (3).  (Recall that Users work for you whereas Contacts work for your customers.)  So if the 'who' is actually folks inside your company, you would work with Users rather than Contacts.  Finally, there are situations where you don't have either Contact or User objects but just raw email addresses.  The classic case here is if you bring in usage information that includes email addresses but not all of them are captured as Contacts.  A simpler example for this discussion would be if you had a field with a raw email address.  Then you could simply say 'for all accounts nearing renewal include the email address in field XYZ.'  One disadvantage of this strategy is that tracking is not as nice.  You don't really know who you are sending it to so reporting is not as easy. But if all you have is an email address, that is what you've got to use. I hope this helps!

Thanks @Gaurav and @Karl - that explains things nicely but likely will explore this further with Gaurav on Wed.
Ian

This was really helpful! Thanks, Karl and Gaurav!