would had agree with you if they would had reworked the dupes system... giving only 20 frags on 250 seals... not to mention she isnt even in any redeemable (pure example im missing 2 fragments to 4 star her)

as for your math is a bit off... you already have 80 fragments of her so if you get her again you either get 20 frags (if you already redeemed her) or get 80 frags of her which with your unused frags makes 160 and you need 180 to 4 star her... also you have to compete with edo yagura on the same treasure... its not like in CN that every edo jinch have their OWN treasure which makes it guarantee to get it at certain seals...

because most of people used alts to send themselves good and easy missions... and sometimes the rewards from packs was good such as full ninjas like old kages to half ninjas like madara edo and you could get enough points for free that you actually could use the shop unlike other events (cough cough summer memories cough cough) that you work with everyone entire week, do the event full and be able to get 1 frag or 2 at best... most events that actually rewarded you for playing the game are gone...