Most scams will ask you to park your money for a period of time where it is not accessible to you. They do this to get enough people involved. In this case, the minimum time for pulling your full money out was 120 days... That gave them 4 months to ramp this up, and the shut it down.

November 2017 Bitconnect reached a high peak. It only made sense they'd have to shut it down by February incase too many people started pulling out their money all at once. That's what people started doing it appears which led to the crash.

Never separate yourself from your money. That's the only way a scammer can gain an advantage.