• Streaming video can be done with Jitsi Meet
• Voice chat via mumble.
• sharing files can be done via pastebin site (if text form) or through other third party (like imgbb).

How is the ability for software that isn't IRC to do things a point in favor of IRC? It's faster and easier to set up one account, one run program, and get everyone together on that program than it is to do the same across 3 or 4 of them.

• Is only compatible with itself so if your system doesnt support the client or the web interface well you're boned.

I've used Discord on a variety of systems and never run into this problem.

• Has very little content moderation.

It has the same content moderation as IRC: whatever the local server admins set up.

• terrible UI.

Your mileage may vary, I suppose. I was able to learn the UI pretty quickly.

• Security and privacy concerns

These are a valid point and the one thing that prevents me from really recommending Discord.