If anything ever sounds too good to be true, it most likely is, and this applies to Bitclub network. The thread linked by jhenfelipe basically summarizes the entire thing, and cloudmining as a whole is terrible idea. Consider other more legitimate options to make money, such as investing in physical hardware and mining, or even trading. There's no way anyone can make sure a cloudmining company's legit, and the operators run away with the funds all the time.

It's likely because they actually use funds deposited to their site to invest in miners, but don't return significant amounts of earnings to their customers. Just because a cloudmining company claims to own hashrate doesn't mean they're legitimate.