The source of the delay is that current cellular chips consume too much battery life, reducing the product’s effectiveness and limiting user appeal, according to three of the people. Apple has begun studying lower-power cellular data chips for future smartwatch generations.

This is an incredibly difficult problem, but anything that negatively affects battery life will be a non-starter for a lot of users. Most days, I have plenty of battery life remaining when I go to bed, but I wouldn’t want to be in a situation where I was running out of power early in the day.