I think comments would be a huge value add. Patreon already has them, the pay wall really seperates out most toxicity.
Even if it was opt in by creator, community building tools for the less technical Nebula creators could be a major selling point to get more similar brand creators to join.
I'd be okay if was even simply unfederated comments (or microblogging), which would likely be better for the creator, but I'd love threadiverse communities for more creators.