Biggest problem in web apps, at least to me, is window management. When you switch to Chrome (on Mac), all browser windows come to foreground. I want to keep Slack as its own app so that it stays in the background until needed. I also want to keep it separated in Dock and Cmd-Tab switching etc.

Would something like this work?

https://fluidapp.com/

Theoretically yes, but then you still face other problems when the website has not been designed to be used as a desktop app. Slack's own application offers e.g. an easy way to switch between multiple teams (I have 16).

I really enjoy a separate app as opposed to a browser tab. For one thing I can push it out of the way up in my task bar. I don't live in Slack and only use it occasionally, so it's nice to have it close by but not in my face. Also, the ability to quickly alt-tab to/from it makes it much more accessible for me.

I tried to use the browser version and it works well enough, but it broke my workflow and was distracting. The app has its own set of problems but at least it lets me work the way I want.