The advantage here is obvious: there is no need to analyze the image, the system works directly with the fact of being underwater. But there are also disadvantages to this approach: visitors have to wear an additional device, which is not always convenient or pleasant. In addition, such systems are more suitable for swimming pools, where it is easier to ensure that everyone is equipped with sensors.
Thus, each technology has its pros and cons. Wearable devices provide direct control, underwater cameras ensure accuracy, and computer vision with neural networks allows for large-scale and flexible operation. In practice, different approaches are increasingly being combined to maximize reliability.