The pass unfortunately does not include many museums / attractions (eg Benaki Museum, Panathinaiko Stadium, Byzantine Museum, just to name a few). The money saving was zero with us. Worse, the Athens Pass is completely unknown in Athens, which means one is not told that the particular museum does not participate, one simply does not know the passport. Also, the exchange for a ticket to the Acropolis and the Acropolis Museum is awkward. For other passes (London, Florence, Copenhagen, just to name a few), there are dozens of participating attractions, you go with a plastic card directly to each entrance (with signs for the local passport), shows it there (it is scanned) and everything is beautiful. Not so in Athens. At the Acropolis Museum, the passport was unknown to either the security man or the lady in the dressing room. Only thanks to our persistence and inquiries at the box office, we were exchanged a ticket for the museum at the group cash desk.
We bought the pass for 2 adults and 1 child to avoid the queues at the ticket office to the Acropolis. For the adults, the ticket was there, the passport was just a note with the note that children under 18 years must pay no entrance fee. The children also need a ticket to get through the turnstile. So we had to hire anyway to get a free ticket. Other visitors, who also bought a ticket in advance, had always received one for the children. The whole thing was very annoying.