I was looking through the avatar shop at the potions today and I found out I could increase my rate of Treasure Battles by 50% for 10 rounds for only 150 gran. Then I thought about this and wondered why ANYONE would ever buy this. Lets do the math:

150 gran = 15 cards from lotto (possibly more if you're like me and have all the 1*s)

150 gran = 1 booster pack from a specific set (only 5 cards, but 2 guaranteed 2*s and a higher chance at 3/4/5)

For a normal player, I'd say treasure battles happen maybe 1/8 or 1/10. For someone with a really nice streak going - maybe 1/2. I've only been up to 9 or so so I don't know what the rate is once you get a star. Either way, I'm guessing that with the potion, the highest rate you might see is 2/3 or maybe 3/4 (someone please correct me if I'm wrong).

Therefore:

150 gran = 10 rounds of 50% increased chance at treasure battles = possibly 2-7 treasure battles out of 10. These probably have a rarity something like lotto - maybe boosters. So let's err on the side of higher rarity, to give these potions a chance. That means you would get maximum 7 treasure rounds at booster rarity (assuming you're on a 10 game winning streak already). BUT (and here's the kicker) - YOU HAVE TO WIN ALL 10 OF THE BATTLES. You have to win to keep your cards - otherwise you're paying gran for your opponents to get cards! You also have to win to keep your streak up to the point where you may exceed 5 treasure battles. That's just to keep you solvent.

Let's drop the price or change it to FM - otherwise it's just a pointless endeavor.