Because MangoCoinz is part mobile app and part cloud system, and the main concern that people have is that .apk files (Android app files) are easy to manipulate. And thats true, but thats where the other part of the system comes into place. The cloud system is there to provide security on that part by users having to validate their coins by syncing and by limiting the amount that can be synced per day.
The limit is there so that it will give the hacker only the max daily coins and the rest of the shady coins will be cut off. They will not be able to do this for long, because we will see this and we will suspend their account. The limit is also there so that someone cant get a lot of coins through other, non hack, methods. Like chucking their phone into a washing machine. Its just fair.
You do realize you can emulate as many android instances on a computer as much as you want all with accelerometers and different HWIDs, right?
It's a neat idea but APK's are too easy to exploit.
Besides, where are your coin details, how many coins do you have? Both security and transparency is lacking to take this seriously.