The seminal financial event of this year, the current decade, and possibly our generation is here: Futures trading in bitcoin has begun.But the derivative that would really damp the current crypto frenzy and make digital tokens a speculator-friendly – if not investment-worthy – commodity, currency, tulip, or whatever, isn't futures. It's options.It's hard to see how even existing futures trading rules can deal with something as volatile as bitcoin.Cboe Global Markets Inc.