Slack/Teams msgs are for communicating, emails are for summaries. rule of thumb: if you're writing an email from your phone it's probably better off as a DM.
Twitter is a mess but there's something here..
for better or worse Meta controls a user's social identity, this could promote a filtered & reserved experience
something all generations but boomers care about..
ever scroll past a meme, chuckle, then look at who insta shows of your friends that liked it and then give that person a silent nod like i c u but don't actually contact them? same.
I wouldn't be surprised if my kids never get a phone number, texting (actual sms) has got to be less than <10% of messages these days and shrinking..