I think there are a ton of services that could be more easily built (at least as proof-of-concept) if this kind of UI existed and developers didn't have to worr

I think there are a ton of services that could be more easily built (at least as proof-of-concept) if this kind of UI existed and developers didn't have to worry about pretty flashy GUIs. Also something like this could have more access to "native" stuff than current browsers.