@odd @frankm Sorry, I got that wrong. Per the website:

Apple Watch Series 3 (GPS) uses the network connection of your nearby iPhone to send and receive text messages, answer phone calls and receive notifications. The built-in GPS works independently of your iPhone for distance, pace and route mapping in workouts. And you can do many other things independent of your iPhone, like measure your heart rate, play locally stored music and pay with Apple Pay.

Although, on other pages it says the iPhone is required so IDK 🤷‍♂️