This is super cool. More options is always good. Something that is confusing about the docs though... is there a desktop application? The screenshot implies there is but I couldn't find the docs to download THAT.
Chatto so far fully commits to providing a great PWA experience. The screenshot you're seeing is of the PWA.
I'm aware that a lot of people want desktop and mobile apps. These will be coming at some point, at least as wrappers around the PWA.