The article alludes to this at the end but doesn't talk the real reason head on. As these are leveraged products the banks are exposed to large swings in the co

The article alludes to this at the end but doesn't talk the real reason head on. As these are leveraged products the banks are exposed to large swings in the contract price via various clearing mechanisms. So they are looking at the volatility and asking what happens when someone doesn't pay and we have to step in and cover them. BTC is a bit of a volatile underlying. If I was in clearing risk I would be worried too.