Once they start this "bounty", all they offer is their token as payment. Token as payment includes whatever manager they got to do their marketing. They collect 1-100 btc and it is almost pure profit for them. They can rinse and repeat the whole process 20x a month.
I heavily agree on this one, when it comes to bounty thing where scam projects comes to a point when they are already rampant or flooding out into the market.
One of the best managers of this forum had spoken so this would be an enough answer IMO.