This seems like an interesting graphic proposal, whose sole purpose seems to be to reduce grinding time.
We have to consider the flexibility that would need to be added to the display of spins, in that it would need to change from 1 to 2 to 3 spins depending on the enemy. Aside from that, I'm not sure how the database would handle getting 3 cards at the same time added to a player's account.
It seems like too much effort for something which should be reduced in the first place, grinding. The extra time from spins may be factored into the balancing of monetary gain / time.