Expecting all devs to test their sites with screen readers is unrealistic.

I disagree with this but its not what we're talking about. You said output is useless and I'm saying its obviously not. There's zero cost to using it instead of a div so the only reason not to use it is to purposefully screw users who need accessibility features.

All those other elements give some benefit apart from accessibility

Maybe for label but p and h1 - h6 only differ from div in styles, which is another argument in my favor. If you're willing to swap a div for one of those for visual users, swapping a div for output should be just as easy of a change.