I think the application for this is to return some dignity and independence to people who have physical trouble washing themselves. Of course the form factor of the 1970 prototype wouldn’t do that, but that can be fixed.

There was a similar (contemporary?) Japanese model shared on here a few days ago, which was basically the same sans ladder. As long as there's nothing to stumble over on your way in, and it's not too hard to get situated in the chair, one of those would be amazing for people with mobility issues.

There was a New Yorker short story I read years ago about an elderly woman in a nursing home, and this wasn't the point of the story at all, but the main thing I remember is how the woman wanted to live with her daughter until her daughter pointed out that assisted/accessible bathing would be impossible in the daughter's tiny apartment shower.

It fills with (hot) water up to the neck, which feels like a huge risk for unattended disabled people

I would be mightily surprised if the independence of disabled people were even a thought in the 70s.