Vaults put your balance to work inside the exchange's own machinery. Every vault publishes what it does, what it earns, and what it risks.
The reserve is the counterparty to every knockout contract. Losing trades fill it. Winning trades draw from it.
Depositors hold a share of the reserve. As the reserve grows, the share price grows with it.
The risk on the label: when winning trades outpace losing trades, the reserve shrinks, and your share shrinks with it.