Good question!
Given a more flexible layout block (right now you can only create equally sized columns and rows), I think that web apps could be built with it. It already solves a lot of the annoying parts (props drilling, state management, component creation, imports, …). In theory you could build a block that can work with a database — anything really because it’s just backed by code. And because you start with an empty canvas, you could build anything. So in a sense it is a framework that comes with its own GUI builder.
The longer I think about it, the more I realize that it could become an operating system that could host all of my apps — with the advantage that apps could talk to each other and share data. Not sure if I want to push it in that direction, but it is an interesting thought experiment.
I think you could use Ratio instead of: online code playgrounds (CodePen, ObservableHQ), Automation tools (Automator, Workflows, Zappier), Code Utilities (Paw, JSON Tree Viewers, API Explorers) and Command Line Tools that are missing a GUI (image compressors, FFMPEG, FTP, …). So mainly developer tools used to figure things out.
The other audience could be “open” personal apps that can be hacked and interoperate. That part depends on the time invested into that area. But the fun part would be that someone could program a “backend” block (e.g. for fetching and sending emails) and someone else could build UI on top of it. And someone else could build a different UI on top of it. And so on … right now the design is very unified, but you can completely change the look and feel if you wanted to. Will try to show something in my next demo 🙂