First of all, if you don't pause while using Apple Watch for strength training, the training data you recorded may be distorted. Because when the watch records data, it counts the training amount by sensing motion. If you continue to exercise during the rest time, the watch will continue to record data, resulting in inaccurate training data.
Secondly, stopping training can help you control your rest time better. In strength training, the length of rest time needs to be arranged reasonably according to the training intensity and personal physical condition. If you don't pause, you will probably rest too long or not enough because you don't pay attention to the time, which will affect the training effect.
Besides, proper rest can give your muscles enough time to recover and grow. In strength training, the muscle is heavily loaded and damaged, so it needs proper rest time to recover and grow. If you don't rest, your muscles won't get enough rest, which will affect your recovery and growth.
Finally, although it may be troublesome for you to pause training, it can help you control your rest time better, make your training data more accurate, and also help your muscles recover and grow. Therefore, it is recommended to take a break when using Apple Watch for strength training. At the same time, if you find it too troublesome to pause, you can do some other training during the break, such as stretching and aerobic exercise, which can also make your training more efficient.