People prefer derivatives above the real thing (because of leverage and possible additional advantages like borrowed funds)
The way I see it is that derivatives are the weapons of the bankers against the threat "bitcoin""
It will always be possible to create promissory notes and go fractional reserve with any asset. However, with Bitcoin, there is always Bitcoin at the core. If you have the private keys, you have the bitcoins and no one will be able to divest you of that value with tricky accounting or by running the presses. For those of us who take the role of evangelist, it in incumbent upon us to make it clear that these financial instruments
are not Bitcoin