The focus on the practical details, as opposed to philosophizing. Even though the focus is literally on atonement. That is, the phenomenon of atonement is functional here, a piece of the avodah. Rather than the need for it being a constant thought and topic of faith. Also, where does the kohen gadol restart the procedure if there is a need? Does he go back to the beginning, or can he pick it up where the avodah had been left off, mid-cycle. Plus, what happens when the procedure of particular Temple ceremonies cannot be carried out. For example, a Nazir who is bald (so he can't cut his overgrown hair). A metzora who doesn't have thumbs (for the kohen to sprinkle blood there, when he is purified from his tzara'at). That is, specifically issues that are not going to be resolved with time.