Contracts are a product that Altcoin can't exploit, and even large exchanges can't maintain liquidity even if they open their own trading platforms. For example, during the recent crash, many small exchanges didn't intervene at all. While it might appear that these exchanges withstood the volatility, in reality, those short contracts at these exchanges lost profits. On the other hand, if this was a targeted attack on a small exchange, BTC would have been wiped out.