That's mostly due to the fact that when the original bitcoin chain split into two, it created a lot of «free» bitcoin cash. (sebfor.com)
Next time there's a major chain split in the future, It'd be really nice if we could do fork futures without a trusted third - party, right? (prestwi.ch)
We're doing this avoid any added complications thanks to this potential chain split, and to ensure that your bitcoin completely secure. (ntrust.com)