When you use Cheat Engine to change your Gold from 500 to 5,000,000, you are only changing the "client-side" display value in your local memory. The moment you try to buy an island expansion, hatch an egg, or restart the game, the local client communicates with Gameloft's servers. The server checks your true balance, notices the discrepancy, and immediately reverts your currency back to the legitimate amount. The Serious Risks of Trying to Cheat
Even if you successfully locate an address, remember that server synchronization will likely revert your changes within minutes.