Crypto venues list options settled in a dollar stablecoin and options settled in the coin itself. They look nearly identical on a screen. They are different instruments.
What actually differs
The payoff shape. Coin-settled contracts are inverse, so the dollar payoff is curved rather than linear — the mechanism in inverse options.
The collateral. A coin-settled position is margined in the coin, which reintroduces the reflexivity from coin-margined perpetuals: the collateral moves with the thing being traded.
Who trades them. Coin-settled suits participants who think in coins — holders, miners, funds with coin-denominated mandates. Stablecoin-settled suits participants who think in dollars. The two books can therefore carry genuinely different positioning, and the difference between them is information rather than noise.
The aggregation trap
Summing open interest or gamma across both books produces a figure whose units are unclear. It is a category error of the same family as blending funding across venues — the arithmetic completes, the result describes nothing anybody is exposed to.
Notional is the specific trap. A coin-settled contract’s notional is denominated in the coin, so converting to dollars at spot gives a figure that changes when spot changes, with no position having been opened or closed. Compare that against a stablecoin-settled book with a fixed dollar notional and the relative sizes will drift for arithmetic reasons alone — the same denomination problem as in open interest denomination.
The practical rule
Compute per settlement type, report per settlement type, and state which one a figure came from. If a single number is needed, name the book it belongs to rather than blending — a named book is reproducible, and a blend is a construct nobody can check.