Overview

Two tokens, two jobs:

Token	Role
USDG	The betting currency. Stakes, payouts, bankroll, and staking deposits are all USDG
CHANCE	The protocol token. An optional payout currency for winners and for staker earnings, and the asset in the protocol’s Uniswap V4 CHANCE/USDG pool

You never need CHANCE to play - every bet is placed and can be paid out entirely in USDG.

Where CHANCE enters the picture

Winners can claim in CHANCE. Choosing claimAsChance takes claim fees from the USDG payout, then spends the net remainder buying CHANCE on the V4 pool at claim time. See Claiming and Acquiring.
Stakers can claim earnings in CHANCE. Unlocked earnings tranches can be withdrawn as CHANCE the same way (claimStakerEarnings with asChance = true). See Staking rewards.
House wins buy CHANCE. A portion of every house win (buyBackFeeBps, default 5%) accrues to a buyback pot that anyone can spend on the pool and burn.

Transfer-locked by default. CHANCE is not freely transferable between wallets until the lock is lifted. Gameplay claims, staker-earnings claims, and pool swaps work; P2P sends don’t. Details: Transfer lock.
Sells are always open. CHANCE→USDG swaps through the public Uniswap V4 router are allowed for anyone, even under the lock. Buys on the pool are gated. Details: Selling.