>> As a consumer, I fail to see the value in having to download large single page webapps that are equivalent (or worse) than their online counterparts.

I use the Slack app for Windows, and the value for me is that it gets its own easily identifiable presence in my Windows task bar.

I have a (self-inflicted) problem with tab proliferation, and because I rely heavily on Slack, it's just way more convenient to use the self-contained version than to have it running in a tab buried in one of my browser windows.

It doesn't bother me at all that the Slack app is an over glorified web browser running the Slack web client.