Wi-Fi calling while in Europe.

I am in Greece right now and I was under the impression that if I use Wi-Fi calling back to the US it should be free. I had phone in airplane mode on so cellular service was off, Wi-Fi calling was on and I was connected to a Wi-Fi network. I believe I used the Wi-Fi calling to call a US-based 800 number which was my credit card provider. I’m using a local SIM for most of my activity, so for this call, I turned on my AT&T eSIM and was very careful to make sure that I was in airplane mode the whole time. Somehow around that time an AT&T international day pass got activated. I went online to chat with an AT&T representative and I was informed that using the Wi-Fi calling is considered  using my service and could activate the international day pas.  The representative told me for this reason that they do not recommend using Wi-Fi calling while abroad.  This information flew in the face of all the information I had gathered before I left from my trip. if what this representative is saying is true, what would be the point of making Wi-Fi call? If I’m activating a pass, I could just use my roaming service to call back to the US. so I’m very confused. I hope somebody can help me understand this better.