The quest potions are definitely something that requires a 'long game' approach. If you look at the breakdown of average value of a loot chest, much of the value comes from very small odds of getting very valuable cards. It means [except for those who are very lucky] you probably won't see a return on your investment after a few potions. You would probably need hundreds or thousands before you approach that "average" value. Then again, one gold foil changes everything! Best of luck on your own quest potions.