Other examples: sequencediagram.net, SwiftUI and React to some extent, vim directory managers (e.g. some let you rename files just by editing text and delete them just by deleting lines)
The only issue is, I've worked on building these, and it's a lot harder than it looks. You can either do immediate mode, which requires fast parsing and rendering and supporting all sorts of illegal values; or you can try to do retained mode, but there are insane #s of edge cases and the effort to compute diff usually makes it slower anyways. Furthermore if you want a really fancy text view, you need to build it yourself, which is a huge project on its own.