@janhenke so a few points on this:
1) there are additional benefits to having an app beyond "it's just native". for instance our webapp has bindings into system notifications, tray/dock, starts on boot, has a "home" outside of the browser so if I want to get to Gitter I just cmd+tab to Gitter and and it feels like it has a place. the same reason that I, like many other people, run and even pay for MailPlane even though it's effectively just a wrapper around a web application. potentially it can interact with other portions of the system too that we currently don't do.
2) our decision to do this is largely down to resourcing. having to build native apps for Mac, Windows, Linux, iOS, Android, Windows Phone is costly. not only one-off costs, but continual maintenance - add a new feature you have to add it to a 6 different platforms, effectively the same thing, but still you have to implement it 6 different times. the added benefit as well is that you introduce a new feature in the web interface and the next page load it's there, for everybody. no waiting for people to update. you can do bucket/multivariate testing easily on the web too, which is an absolute nightmare on the desktop.