Can you use valueAtTime in Ae to automatically follow another layer with a delay? Yes. Yes you can. I always look forward to the Felt Tips quick tips or hone he answers a question from the video hive forums, as I know they will always impart great wisdom.
how to get After Effects layers to follow the animation of another layer with a delay
Here, Felt Tips show how you can use the Expression valueAtTime in Ae to have a layer follow the motion of another while also creating a staggered delay. By setting timed delays to animated layers you can get all kinds of interesting motion happening.