As much as I'd love a native app, for a fast moving company with rolling releases it's probably very hard to keep three platforms at the same level especially if you want to do experiments too or roll out features to a small subset.
Name three major feature improvements to Slack in the last three years.
I can think of one, threads, which are a fucking usability disaster and should have been killed immediately. I can't think of a single other major feature.
I use it for incident updates internally too so the discussion is grouped. Much easier than paging through the channel.