Up/downvotes help us all essentially be eachothers “algorithm” so its easier to find interesting stuff. Also comment sections are the best part of Lemmy style websites while mastodon is a mess to follow because the default app doesnt even have threaded replies, theres no downvotes, and you cant subscribe to a post to get notifications or come back to it later and posts dont appear on google searches so a post doesn’t get any use after a day or two. Lemmy posts bring me benefits months/years after theyre made because they appear when I google for information