Synthetix Perps are range of Perpetual Future markets, fully on-chain and available to be integrated by anyone. Synthetix does not offer trading, but many front ends have decided to build interfaces and offer trading.
Synthetix - Decentralized Perps
A list of currently available trading interfaces, with varying additional functionality
Developers may be interested in building a front-end, or integrating an existing platform, to make use of very low slippage, low fees, and fast execution perpetual futures trading.
There are currently two relevant incentive programs
SIP-2003: Perps V2 Trading Incentives
Reward traders for using Synthetix Perps, via an integrated front end
SIP-2002: Revised Volume Source Fee Program
Reward Synthetix integrators who drive volume through Synthetix