Wi-fi calling, when on, will utilize the wi-fi signal if your carrier signal is weak or has interference at the location you are making or receiving the phone call. Most times, even though I have my wi-fil calling settings to "cellular preferred", inside my home It is always on wi-fi, even when my cell signal is strong. I don't care, as long as I get and can make calls. Turning the wi-fi calling off, you may find you are not receiving some calls.
