I tried using them for a while but they only got in the way more than they were useful for me, and since I don't really find myself constantly talking to anyone I turned them off to save myself the headache.
Maybe they're useful to people who constantly text each other, but for me? I'll just stick to the notification quick reply if its urgent.
I'm also having the same issue, I never got the email after signing up, I tried sending a DM from another smaller instance but it doesn't seem to have gone through