The site generates income from several different sources < income from gambling / mining / advertisements > and all of these are used to fund the different payouts. The few Satoshi's being paid to people are but a mere drop in the ocean of the total profits that are generated from the site. < As you said, most people use their Free roll to fund their gambling & lottery ticket expenses >
There is nothing sinister in this model, they are just magicians to shift money from the different income streams to fund their expenses. < There is most definitely a science behind running a successful faucet >
The Lottery is the only aspect of this site, that might be a bit dodgy. < this cannot be proven >