I would think running stuff other than just a web browser is the use case. The device goes from portable web browser to Linux laptop with every tool a professional developer uses at your finger tips (and a web browser)
I'm not at all claiming Chrome OS or crostini are without problems or limitations, but I have been very happily surprised at how well it stood up to some basic web dev work.
I’m not the brightest crayon in the box, I spend most of my life in the debugger!
https://blog.stackblitz.com/posts/introducing-webcontainers/