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 mentioned above but Godot has a low processor mode that gives you some control over the refresh cycle when nothing is happening. I doubt this completely alleviates the problem but I think it's worth profiling it for individual use cases.