One big benefit to a much smaller community (like Mastodon) that I can already perceive: it's impossible for someone to just retweet (retoot?) like-minded toots as 99% of their contribution. At least at this scale, if you want to participate in a discussion, one must think for themselves, which is a huge win for everyone involved.
@erik There was an article I read a few months ago where a reporter figured out a method to remove all retweets from their timeline. They said the overall Twitter experience improved for them with retweets gone, so hopefully you are correct.