I believe that if S2X catches momentum while the legacy Bitcoin doesn't, and if other exchanges decides to use the BTC ticker on the S2X-chain, then it will be very hard for Bitfinex to follow up on their promise. In any case, such a promise places Bitfinex clearly in the landscape as loyal to the "Core movement".

The Bitfinex futures is a bit skewed, there are quite many conditions that would render one of the tokens worthless, and I can imagine that several of those hurts BT2 more than BT1.

The T&C was quite lengthy, and I think the most unacceptable part of the conditions is that Bitfinex can change the Terms and Conditions any time. If placing a bet, the conditions should be as simple as possible, as well-defined as possible, and certainly immutable! If betting between outcome A and outcome B, and the completely unexpected outcome C happens, then the bet should be cancelled. When knowing that the exchange is "Core-loyal", it makes the BT2-bet even more risky.

Despite all this, I did buy a little bit of the BT2 future - the possibility to grow 0.3 BTC into 1.6 BTC was quite tempting.

I would love to see some similar futures option from more exchanges, I think we'd see different pricing dependent on the exact wording of the T&C, as well as what stance the exchange has on the fork.