Earlier quoted context omitted.
I'll give you an up-vote because I think a variety of different viewpoints is important, but I'm very much in the e-mail camp. My biggest reason is simply: it's the only ubiquitous, decentralized, open protocol that I can think of. I can run my own server if I want, an I can interact with anybody with an e-mail address . Sure, there was XMPP for IM, but that doesn't have wide adoption; same with other protocols.
You really can't run your on email server nowadays though, you need to have been running one for several decades otherwise the email common email providers(gmail, outlook) will automatically just assume its spam. Also due to the way extensions added to the email protocol configuring and learning how to properly configure it so it gets accepted will be a dayjob.
I've run a personal mail server for the last 5 or so years and I have SPF, DKIM, DMARC setup correctly, get 10/10 for mail-tester.com and get graded "not spam" for all the other spam tester sites. Spam Assassin loves me and I have a .com mail server.
I can land more or less into personal emails (occasionally I get filtered into spam), but when it comes to corporate emails I pretty much get /dev/nulled each time and can't even land into a spam folder. I can't give out my personal email as a point of contact and have to use my gmail or protonmail instead.
I've all but given up on owning my own email because the protocol has effectively made it impossible to reliably land mail in a mailbox if you don't have a certain amount of outbound mail traffic.