To paraphrase my opinion from back then:
- Easier onboarding, and a familiar, easier UX
- customizable feeds you can subscribe to + starterpacks instantly give you full timelines and people to follow (and followers, if you're in many starter packs)
- better discoverability, and therefore higher engagement
- stacking moderation and excellent security features (e.g. detachable quote boosts, "the nuclear block")
- many users who tried Mastodon first had bad experiences with "HOA"-like behavior and over-enthusiastic mods
What S_H_K said, people have reported being rebuked for posting pictures without ALT-text and not CW-ing uncommon things like eye-contact or food, for example. One person notably received angry messages for posting about cutting their finger on a sheet of paper without CW. The worst accounts were of POC talking about racism they experienced and being told to put it under CW.