No one knows; many people are putting almost $1,700,000,000 (Billion) of trust into a small group of people.  Unlike Bitcoin which is totally decentralized, Bitconnect is closed source and completely controlled by an unknown group.  What I can say is that they've been paying for a long time and have tons of capital to stand on.  Many people have made lots of money investing in Bitconnect but the same can be said for many 'ponzi' investments.