The two contracts are BTC:USDT perpetual and ETH:USDT perpetual. This means they have linear payout structure and USDT is the collateral and PnL currency.
The unique part of the offering is not just the USDT collateral (inverse crypto dominates the market), but also the way the rate is set. Instead of an ongoing funding rate, the contracts charge the premium/discount for going long/short upon execution of the trade. This means no carrying costs bleeding you dry while you are in a longer term position.
However, the volume on these new contracts has been shockingly bad. They barely crack 0.01% of marketshare compared to the broader derivatives space in crypto. There are a number of reasons why this has been the case:
1. Verification required - because the contracts use USDT and because BitFinex has had run-ins with the CFTC in the past, they have required all derivatives traders to be verified accounts. This is a major restriction that just does not exist on the top exchanges.
2. Requiring USDT - these contracts require that the trader have USDT, so in essence the products are being used to help drive use of USDT, but the reality is traders have crypto and want to earn more crypto going long or short, it is that simple. By not allowing traders to use their BTC or ETH or other to trade, they are missing out on a huge part of the market.
3. No marketing - they have not been very loud about the derivatives offering at all. This is partly due to the regulatory environment where they have to be careful how they promote derivatives. But either way, people won't trade unless there is more noise about it.
4. Education - because it is an unusual perpetual futures contract (linear payout, using USDT, unique funding mechanism), traders are just not familiar with these aspects and there should be a more clear guide for how they trade, including a demo version.