The allowance system seems like it's in place to discourage unhealthy practices, which would be my immediate guess, since potentially doing over a hundred in a day would become extremely time-consuming; I'm not saying whether that's necessarily the right action, but I'm trying to guess a developer's perspective. That, or they want more reasons for you to log in on different days, which is financially wanted for a subscription-based model... or it could likely be a combination those reasons.

Personally, I think there's some economic in-game market value in those allowances being limited, based on what some other reactions have mentioned; making them truly unlimited seems concerning to me, but that's just my subjective opinion, and I would need to think about this more as well.