You have only one UI for all text chats, no need to remember on which app you talked with your cousin and on which app you talked with your friend. All of them are in this one app.
About the downvotes, this is not the first time that has happened. I have been repeatedly getting downvoted on some of the tech or related communities on Lemmy instances recently for completely innocuous comments. Since I am on kbin, they don't impact me in anyway, but I have been puzzled about it. The only explanation I can come up with is something I wrote at some point offended someone and they are just down voting whatever post they see of mine with multiple accounts.