If this card is ever successful I think it would/should be a rare card (not that it has much impact).
I agree, in very limited situations this card could be stronger than miracle depending on how much max hp you have (and essentially you could have 12 miracles in a entropy/light stall - although this card would get only 75 hp from 2 full quanta pools minus the quanta to use this):
PENbow with rainbow quanta based on QP, if it gets even 1/2 of max quanta (average of 37 in each - round down to be kind) = 6 x 37 hp gained (12 x 37 x 1/2), which is 222 hp gained.
Thus, this card is around the same potential as miracle within an earth/light 500 EM deck - but outclassed in that situation by miracle as miracle could heal 498 while this could only heal 75 minus quanta used by this.
It is definitely more usable in a SNbow than miracle - as the base cost is much lower, allowing it to be used compared to trying to use miracle with only light quanta from SN