Fine, if they don't have any business reason for a native client they should just can the slack desktop app because it provides 0 benefits over the web app then.
If you're going to do something do it right or don't do it at all.
The desktop app allows them to Mark the checkbox of having a "native" app when selling ... And in my environment quite a few folks prefer the election app over the browser. I don't know why, though.
I prefer a dedicate app because I can alt-tab through a relatively limited number of apps compared to the dozens of tabs I may have open.
For example, the desktop app will show notification count in the dock.
Imagine if all of your apps had a browser version and you could always pick between a tabbed version vs standalone version. To use the tabbed version of everything would be like using an AOL app back in those days where you alt-tab to the AOL virtual window and then find the app you want within it while wishing you could just use the OS' window manager system.
If you're going to do something do it right or don't do it at all.