That was essentially my envisioned use case, as well. Not only for devices that won't run JS but those where you might not want to. For example, a lot of news websites are surprisingly JavaScript heavy, slow and buggy, not something I necessarily want to run if I merely want to read what the news is talking about. Public read-only sites. Granted, arguably services like outline.com and archive.is already cover this use case better.
As for sites requiring credentials, the way I see it users could run the cloud browser on their own server. This has benefits even for public sites, adding additional privacy. However it is not something this Cloud Browser really supports yet, since there is no support for forms, text fields, or other interactivity with the exception of hyperlinks.
I've been toying with this configuration and think it might be usable for some opensource projects.
Second: If my cloud browser has all of my credentials, do I care that my cloud browser is the process that’s pwned instead of my local browser? I think I don’t, so the main benefit would seem to be something like “view a certain static-ish subset of JS-required websites on a device that can’t/won’t run JS”.