We may have limited boxes for this event but, as most of us know, we’ve got the Christmas 2019 and Da Vinci unlimited lotto events coming up soon. With enough boxes you can solve any number of problems from resolving EXP shortages to (temporary) escape from QP hell. You may even be saving up the mats and embers for future roll targets.
In essence, what are you wanting out of your lotto boxes and what issues are you planning to resolve?
For me, I need embers so I will be leveling servants like crazy afterwards. There are also far too many batteries which aren’t leveled due to QP and/or gem limitations. I want as many servants and skills leveled as much as I possibly can.