We've turned on Wi-Fi calling on both Chef Elaine's iPhone and my Google Pixel 7, providing our phones a second path to our cellular network providers. The phones will select the best signal available and even seamlessly switch between the two. As you can see in the picture below, my phone (left) shows an "Ongoing Wi-Fi call" and the Chef's (right) has "VZW Wi-Fi" in the phone icon in the status bar. This is not a money-saving option (we have unlimited minutes), but rather a quality improvement as our home Wi-Fi and Internet setups are stronger and faster than the signal from the nearest cell tower.
Learn more about Wi-Fi calling at the links below.