I think my friends just described how you can benefit from the Domain Model again through the discussions of presentation services.
Even though you focus on the core with the Domain Model, that's not the same as saying that the presentation service is less important. On the contrary! The importance of the presentation service is one of the reasons why you should work hard on the Domain Model. By moving out as many things as possible from the PL that are just distractions in that context, it is easier or more possible to create a first-class UI.