This seems to answer the question of what is done with the money and how they get the returns (from the website's FAQ @ https://leancy.com/faq/#q9):

I would like to invest my money in a particular startup. Is this possible?
No. LEANCY distributes your funds as a trusted investment advisor and does not disclose the details of its portfolio management strategies, since this information is highly sensitive in terms of market competition. The system is oriented toward quick and convenient money making where the entire task of portfolio management is delegated to us.