AFAIK Bitcoinica was the only site offering BTC derivatives, so presumably some people figured the potential profit was worth the risk. More generally, all Bitcoin exchanges seem to be run by amateurs, so people have to deal with them to cash out.
Derivatives as in options/futures/swaps/even more exotic?
That is quite possibly the scariest financial product ever devised, assuming there was nobody putting together complex products based on Zimbabwean currency during their period of massive inflation.
I wonder why. There seems to be a huge gap in the market for a professionally run enterprise here. Or at least, anything more focused beyond students half-assing it part-time.
Bitcoin market activity may not be large enough to ever pay back the significant cost of building a secure exchange. Also, as TradeHill and CampBX discovered, people just won't move off of MtGox no matter how bad it is.
People won't move off of MtGox for a simple reason: it has by far the best liquidity.
The only way for another exchange to get a foothold would be to offer similar liquidity, which would mean taking the other side of most trades themselves. This would be very risky and they would need deep pockets.
