The main target of the Godot Engine are game developers. But Godot's easy workflow and functional UI elements, makes it also a good fit for non-game applications. There are already some out there you may know, like Pixelorama, an Open Source 2D sprite editor.
I know many Mac users who use Safari just because it’s doesn’t drain the battery as much as Chrome. That's a big difference for desktop applications, and constantly redrawing the window at 60fps definitely will kill your battery.
For sure! However Godot has low processor mode that lets you control the frequency of the update when no changes are being made. That update time can even be changed from code so you can adjust it situationally.