I also want to know this! The new "big" watches have WiFi built in and I prefer it over Bluetooth. The communication between watch and cloud is mainly done by Android or iOS driven hardware. But I have to use Garmin Express and a Windows driven hardware to set up WiFi. If I am not at home I only have non Windows smart products with me. So no chance to set up my watch for a new WiFi connection in Holliday.
CW - It's a bit harder to enter the WiFi password without a keyboard, but I tried it and it works fine! I'm not sure when it was added (what FW version)