SMS is evil and no one should use it under any circumstance, since it requires users to disclose their phone number. My phone number is absolutely privileged information.
iMessage is just SMS but worse, and also assures that any binary attachments are mangled by Apple before they are delivered.
Whatsapp and Facebook messenger are evil because they are owned by Facebook.
Signal is just Whatsapp, but owned by a couple shady-ass Russians. Also: no one uses it.
Telegram has all of the privacy bona fides and about 1/20th the user base of Signal. Also they dropped support to act as an SMS replacement on Android, which took away the most compelling argument that could be made for having it.
Teams is evil because it's a separate thing from Skype, a product I actually used to kinda like that no one uses any more, and I'm not OK with having multiple chat services from the same goddamned company on my devices. See also: Google Duo and Google Allo. Are either of those still a thing? I have no idea.
Discord is evil because those fuckers can't be bothered to open anything up for web indexing. These days I check what available support options are for hardware and software products and if I see something about Discord, I just won't buy or use that thing. This one is especially important when it becomes clear that the responsible party in Discord chat is clearly irritated that they have to answer the same questions multiple times a day, yet they don't have any kind of support document elsewhere. I got rid of my Snapmaker printer after learning that the only meaningful support for them was Discord.
I will reluctantly accept Google Chat or Snapchat. I have a Google Voice number that I give to things that absolutely think they HAVE to be able to send SMS messages. The number isn't tied to a real phone. I just receive emails of whatever texts or voice mails people leave.
Email is on the other hand perfect. It's easy to understand, easy to filter and easy to script. It works on a potato. I can make IFTTT triggers. Everyone can have as many addresses as they want. It does not have the power to make my phone ring, and I can delay responding or treat it as real time as necessary. I cannot understand why anyone would bother with anything.
Reading all this, if you think that I do not wish to be contacted, you are absolutely correct.