An iPhone is necessary in the download and setup of WorkerSafety Pro solutions for the Apple Watch. However, once you have WorkerSafety Pro fully set up on your watch, you no longer need to run it on your iPhone. At this point you can pause the app or quit it altogether on the iPhone, but do not delete the app from the iPhone. It will still be running on your watch and monitoring for falls.
If your Apple Watch has LTE capability (its own phone number), you do not have to carry your iPhone with you when you go out and about. However, if your Apple Watch does not have LTE, you must carry your phone with you, but it doesn't need to be on your person. This is necessary because your watch needs a connection to the internet and it will do this via Bluetooth with the iPhone.