That's because Yom Kippur (when it's done properly) addresses only one year's sins
and no more than one year, i.e. it's only applicable to the past, never to the future,
viz: as soon as the annual ritual was completed, the Jews immediately began
accumulating sins towards the next Yom Kippur resulting in a do-over of the same
ritual all over again; year after year after year ad infinitum, viz: Yom Kippur
addresses only that part of a Jew's life that they've lived up to that point; never to
the part of their life that they haven't lived yet. In other words: it addresses a
portion of their life instead of their entire life from start to finish.
In contrast: the past, present, and future of folks unified with Christ is addressed
by Isa 53:6 because God, in some mysterious way that I've yet to fully understand,
accounts them joint principals in His son's crucifixion.
● Rom 6:3 . . Don't you know that all of us who were baptized into Christ Jesus
were baptized into his death?
● Rom 6:6 . . Knowing this: that our old man is crucified with him
● Col 3:3 . . For you died, and your life is now concealed with Christ in God.
NOTE: The word "concealed" is relative to old covenant atonements that provided
Jews with a liturgical means for covering their sins; in effect obscuring them from
view. Those atonements were far from ideal, whereas Christ's is the cat's meow.
(Heb 10:14-18)