I don't know if this has already been proposed, but I suggest to put the "use in batch" option for the optional packs, since it's rather long and also annoying to have to select and open these packs one by one, especially when you have like 50 or 100 of them (both for ninja fragments or refine for example).

Since this function is already implemented in the game I hope it will not be so difficult to add it for the optional packs.

If a user has for example 100 refine packs and needs to use them to take 70 medium and 30 advanced refines, the "use in batch" function may let him select 70 of them the first time to buy the medium refines and then 30 of them to take the advanced, all in two clicks.

Let me know if it's feasible, thanks for your time.