There are many projects which pay some bounty for making their community and some project do not pay for making or increasing the community but they only pay for promoting their project. The second one will get a pure community because they do not impose anyone to join their chat channel or any group etc but they only spread their project and those who visit their project and find it beneficial for them join the community.

While the first one collect only those people who will come there to join the community only for the bounty.