Yes, it’s just an IM client. Like all in history, what matters is whether it can post images and whether other tools are integrated with it. Another generation will invent a new one and suddenly all app will say “Insert your $nextGenChat key here”.
You can rebuild a chat client, but you can’t make up for popularity. Atlassian tried twice: Once with HipChat, once with Stride, and failed at both - like everything Atlassian does, I know, but you have to admit they are popular in corporates.
Also, it’s so vastly better than MS Teams. But Discord is so vastly better that a lot of companies use it, despite it being aimed at communities.
Honestly I preferred Google hangouts because they were better integrated with my email.
Channels as far as I can tell are a mix of group chats or replacements for mass email distribution lists. Nothing special.
Also point 7in this blog is truly insane. The whole point of a dm is I don’t want others to see it.