If the fork does not happend, those who have BCU, these BCU could not become BTC?
Supose you buy 10 BCU, after december 31st, if the fork doesn't happend, these 10 BCU may become 10 BTC?
If the fork does not happen the price of BCU will go to zero. Buying BCU is a way for you to bet the fork WILL happen. If you bet on a horse to win and the horse does not win then you lose your bet.
Same thing here.
Only buy BCU if you think the fork will happen (or you think you can dump them for a profit on some other sucker that thinks the fork will happen).