Looks like this is now rolled out to Skype for Business Online. A much prettier experience. Before you ask still no WebRTC/plugin-less join, we’re seeing WebRTC/ORTC progress on the Skype consumer side, hopefully this makes it’s way to Skype for Business soon.
This is now the experience when you click a link for a Skype for Business meeting and don’t have the full client (i.e. a guest on a PC without SfB) or just choose to join via the Web app.
1 click install, then the installer disappears