Treasure Chest Opened After Watching Ad

I opened the Old Treasure Chest in the Elf Forest after watching an ad, and got 500 gems. It was a 5% chance. I'm happy it wasn't experience points. Old Treasure Chest in the Elf Forest Item Probability 500 Coins 0.1% 3,000 Gems 1.5% 5 Gem Booster: 1 Hour 1.6% 5 Gem Booster: 30 Minutes 2.5% 1,000 Gems 3% 500 Gems 5% 10,000 EXP Up 18% 5,000 EXP Up 28% 3,000 EXP Up 40.3%