That's exactly the point. Here this is the fireplace.

You will find western style "fireplaces" in some new homes which are nothing more than show pieces to have cosy atmosphere but are utterly impractical for the task of heating the home.

Now, what what we would call "heater" is usually placed in the basement for practical purposes. The ones I showed above are placed directly in living area and are way more efficient.

Traditionally, you did not heat entire home, only the area where you live which contracts during winter. There might be other rooms which you only heat in the evening before you go to bed and then it gets extremely cold (but that's fine, you just put good enough featherbed to keep warm). This is practical aspect because heating entire home requires huge amount of resources.

There are plenty of manufacturers making glass fireplace inserts that are designed to be combined with a heat accumulating flue systems. Romotop or Hoxter are examples of fancier ones. The finished stoves typically are specced to retain 50% peak heat output after 12h, 25% after 24h. Combined with automated dampers you just load the firewood, light it and can then basically forget about it as the automation takes care of regulating primary and secondary air and shutting air supply off once the fire is done burning.

Anyway, just as you mentioned, this requires enclosing the fireplace (even if with glass) and it requires that the heat is routed somewhere else rather than directly to chimney.

This is 101 of building a functional fireplace designed to heat the house.

No one in the US builds or uses functional fireplaces to heat the house. We have not done so for over 100 years. Any fireplace you see in the US is a decorative feature designed to look nice and set a 'mood' for a room. There are some off-grid wood-heated homes, and some places will have fireplaces designed to efficiently heat a room or two, but statistically these are so close to 0% as to not exist and in many locations it has become illegal to install wood-burning fireplaces due to the air pollution they cause.

This isn't really true. My parents build a house with a large fireplace in the living room. True enough it actually sucked warm air out of the house (tall chimney) and made the whole house colder.

My folks simply bought a really nice fireplace insert. It works extremely well. These are not uncommon, even in the south, and my parent's place is far from 'off grid'. They absolutely do use it to 'heat the house', and we only supplement with radiant heaters in the far bedrooms.

I think you should visit small town/rural New England. A good part of the population around here heats exclusively with wood but usually with a free standing stove or insert.

I think I went back and forth about adding a footnote to 'no one' to quantify before deciding against it. There are still some left who heat with wood, but only a percent or two. It seems pellet-based units are slowly taking over the biomass-heating niche, but I am sure old guys in flannel with a couple of cords of wood up against the side of the house will never disappear from the northeast.

I think you misunderstood. I don't have anything against fireplace as a completely decorative element. Just don't expect it to perform the function of heating the house.