Romans had similar. It's a popular concept through history, but the whole "one hole in the floor" and you could die. Put a damper on it's widespread use.

It's not a matter of it getting built shitty, its a matter of it getting lived hard. 10 years after install, foundation shifts, gap opens up... Your guard is low because it's worked fine for 10 years...

It's why we use hydronics now, same benefits, less dangerous.