Their desktop app is just a wrapper. You can "appify" it using Chrome or Webpin (
https://github.com/artemanufrij/webpin/) or whatever.
Since I have to use Windows at work, I can guarantee you're not missing anything by doing that. I just keep it in a pinned tab in Firefox and use Alt+1 to quickly reach it.
What I am bothered with is the lack of official API which makes it difficult to auto-populate some stuff.