Currently "other" cards take their cost at random from your quanta pools, this may not be a big deal for monos or duos, as they will generate the desired quanta next turn anyway.
With trio or more element multies, the quanta drained from an other card can equal loss of multiple turns or even worse, the entire match. (oponent has a bunch of 2 attack creatures, and the SoG drains 3 of the quanta needed for a shield you lack 1 quantum for to play)
This problem particulary affects quantum towers, or rather decks that use them, as the game quite often simply refuses to generate more quanta of (desired element) for a few turns.
This random quanta draining often stalls a rainbow from using SoGs in hand, because they risk losing due to lacking key quanta for a creature/weapon/shield needed for their strategy.
My suggestion for this issue would be to pick the quanta used to pay for the other card, by making the quantum icons clickable.
