I did a poll and nearly 30% of the people who voted said they used Sync! It's stayed around that percent the whole time too!
EDIT: Here is the poll I forgot to put this here like five times lol https://strawpoll.com/wby5A21R1yA
You are talking about instance and OP said he's used the biggest(actually 3rd) community which does not require its users to be from lemmy.ml So I don't see your point