Second, booming support would attract inauthentic content from people chasing rewards before audience, which I think would detract from the goal of audience building.

There are many users who are dedicated to seeking rewards instead of quality, they just copy and paste until they are detected as plagiarists, but in reality these are not main accounts for this reason they do not mind committing plagiarism. And I agree with your points for the moments the community does not meet the requirements to opt for a booming support. If you start to check the publications, most of the images are taken from google. At least the cover of the post has to be authentic, it could be designed on canva the rest is up to the curators if you meet the requirements.