Everything is very simple, they are afraid to distribute the received ETH and BTC from investors, as the market situation is not stable now. Its easier for them to distribute their currently useless token, which essentially does not cost anything yet. And they need ETH and BTC in order to support the life of the project in difficult times, because good projects have staff that work for salaries. The salary, while the project has not brought profit, is taken from the money of investors.
This is not only a matter of fact, since most of the projects are scammers and they dont want to share earnings with participants of advertising companies, they just pour these tokens onto the participants, make a very cheap listing on a bad exchange and disappear with funds in an unknown direction and once a month give signs life news that doesn't get any easier. They release news so that they would not be sent to prison.