Thanks! And two good questions;
(a) I decided to do that for the analog clock because it is easier to create, as a “slower start”. If you look at the Digital Clock sample, I am using the fps of the scene in the control, as you suggest. However, using a property of the scene does not work well when we link the object, since the scene itself will be linked, so I wanted to delay that explanation a bit. I will talk more about linking and appending in a video in the end though.
(b) That would have worked as well. Any “behind the scenes” values can be done without objects or bones and just values directly, but I chose to do it through the location of an empty to make it more visual. However, having a driven property added to the Clock empty would expose a value that the user should not see, since it can’t change it directly. So even if I decided to add a total_seconds property, I would not want to add it to the clock empty anyway.
But you are right, I should probably have mentioned that in the tutorial.
I hope that answers your questions!