We've had this exact conversation in this community two months ago already, in case you want to back read the comments from back then. Nothing significant has changed

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