IM sucks hard. IM used to be great when it was based on open protocols so you could download Trillian on Windows or Adium on Mac and choose your client and communicate across a wide variety of protocols from the same context.
Now you have to download and run massive resource hogging apps like Team and Slack to simply communicate on 2 protocols.
Matrix protocol has over 60m publicly addressable accounts, and that's not even including all the EU gov, healthcare, military or emergency services. You can even bridge closed protocol apps like Messenger, WhatsApp, Discord et al to your own Matrix Synapse server and get it all in a single client. Works great. Been using it for over a year, can even send files back and forth to people still on Messenger.
Now you have to download and run massive resource hogging apps like Team and Slack to simply communicate on 2 protocols.