get the infinite flip upgrade and you might like to have tins of coins when you can jsut move the curcor in circles in the screen and it flips coins, isntead of having to aim for eahc of those 6 coins.
fever seems utterly useless though, with like a ridiculous 0,3% activation chance to have like 2 sec (at max) time where the flip area is slightly bigger and is red isntead of white.
fever aint worht it, get the needed first upgrade for it and be done with it.