Every orb you pick up goes into your backpack, not your balance. Fill the pack, walk it back to the sell pad, and it becomes coins you can actually spend — on speed, on capacity, on the next island, and eventually on a rebirth that wipes your progress in exchange for a permanent multiplier.
The catch is the walk back. Step outside a safe zone with a full pack and everything you are carrying is on the table. Other players can take it off you. So the interesting question in CoinGrabSteal is never “where are the coins” — it is “how much am I willing to carry past that guy with a bat”.
Underneath, the game is built the way a game that handles other people’s progress should be: the server owns pickups, purchases and rebirths, clients only ever ask, and every request is rate limited. Balance lives in one shared config file, so tuning the economy is a single number in a single place rather than an archaeology dig.