To address your first point (my other comment was focused on the second): You do not need to search every time, this type of app can be saved to the home scree

To address your first point (my other comment was focused on the second): You do not need to search every time, this type of app can be saved to the home screen. You could think of it like a bookmark to a tab that will run chromeless in it's own process (so no access to cookies etc. in your main browser process). For all practical purposes it is a low-privileged "hosted" app like any other - has it's own icon, possible to terminate, sandboxed and so does not share data with other apps. FirefoxOS has a feature that allows you search and browse a set of these apps provided by everything.me but it's also possible to do this directly from the built-in browser app.