Traditional derivatives markets are built on dated contracts: a specific expiry, a settlement, a roll. Crypto’s dominant instrument has no expiry at all. Understanding why explains several things about the data.
No roll
A dated future forces a decision at expiry: close, or roll into the next contract and pay the spread. For a trader who wants continuous exposure that is recurring friction and recurring cost.
A perpetual removes it. The position simply continues, and the cost of holding is paid continuously through funding rather than in a lump at each roll. The same economics, spread smoothly and without a calendar.
One book instead of many
Dated futures fragment liquidity across expiries — front month deep, back months thin. Perpetuals concentrate everything into a single book, which for an asset class that started small was decisive: one deep market beats several shallow ones.
It is also why crypto’s options market looks different. Options must have expiries, so they fragment across strikes and dates, which is part of why a real options book exists on only a handful of coins while nearly everything has a perpetual — the split that decides whether there is a gamma map to read or only liquidity structure.
Continuous markets suit a continuous contract
Expiry conventions exist partly because traditional markets close. Settlement happens at a defined moment because there is a defined moment. Crypto never closes, so the natural design is one that never needs a settlement point either.
What it gives a reader of structure
A cleaner dataset than dated futures provide. Open interest is not split across expiries, so it measures system leverage directly. And the cost of carry is published continuously as funding instead of being inferred from a term structure — positioning that other markets estimate, crypto simply prints.