Exactly. However, this would be SIGNIFICANTLY cheaper if one accepted a second app for door communication. Or one compromises on the "customizability" or "aesthetics" of the whole thing. Based on the expressed wishes, you come out with, for example, the HS, or with PEAKnx/Youvi – or you take something from the DIY corner.
On third-party devices (not, for example, manufacturer-owned touchscreens), there is a small additional app for door communication that only appears when someone calls. It then looks like a FaceTime call and is not even noticeable as an "additional app." However, a fully integrated solution is required here and alternatives (Eisbär) are not desired. Therefore, one stays with Gira, and that is by far one of the most expensive providers, but unfortunately not the best for this kind of thing. The expensive part of the whole setup is the home server and its commissioning as well as the door intercom (with its very modest video quality).