I can assure you that most new construction in Oslo (pretty much only apartments these days) don't include fireplaces. And why would they? With steam pipes running through much of the city, there's no need for the expense and pollution involved with a fireplace except for show anyway.
The fact is that cities in the US, like in Europe, generally have very reliable power and gas supplies, so they don't need to build fireplaces designed to actually heat the place, and we don't want to encourage people in cities to burn wood to heat their place anyway. So showplace fireplaces, especially the gas ones, are a better solution for allowing people to have the cozy feeling when they want it.
I do have a fireplace and a wood stove which provide something of a backup but won't heat the whole house and only work if I'm there.
The modern ones with afterburn contour are also quite efficient in energy output per unit fuel burned.
The considerations are different, though. Cast iron is great if you want to radiate as much heat as possible as fast as possible or need to heat a small area (e.g. single room per heater). There's a reason small cast-iron Jøtul fireplaces used to be the stereotypical heater for cabins etc. in Norway.
I have natural gas heating and a combi smart boiler which runs on electricity. Even if I still have the gas link operational, if my power goes down then my heating is dead.
This news of Texas actually reminded, that I should have some sort of emergency winter heating backup, and a boat or camping kerosene heater is a actually a pretty solid idea for emergencies.
You don't need to go overboard with tons of dried food and a nuclear fallout shelter. Just a cheap multi-fuel camping stove and some canned food will last you a few days easily.
I think Cast Iron or stone fireplaces serve a different purpose, in most cases. They're for show, and novelty.
But more importantly - the gas fireplaces are intended to look nice with minimal effort. They are explicitly not intended to change the indoor climate much if at all. They're usually built in very new homes that have dedicated, reliable climate control systems or in cities that don't require much heating.
They are a bit like windows: not energy efficient but nice to look at/through.
During the historic cold weather going on this week, I have no confidence that they would help if the power went off.
Yeah. There are decorative fireplaces. The Norwegian company Rais sells some great decorative ones.
There are also incredibly efficient cast iron stoves that some people use for heat. You made fun of them in another comment, but they are much more efficient than a fireplace, and can use a variety of fuels like pellets or gas in addition to wood.
Of course, there are also people that have a standard wood fireplace that you imply is in every Norwegian home. Most people don’t use them here since they are so inefficient, dangerous and illegal in cities due to the pollution.
American fireplaces in general are a joke. You are just spending way too much energy and not really storing it anywhere except the air around it. They are built to look good, not to actually heat anything properly.
Check any Nordic country, we don't have gas fireplaces nor do we have the silly tiny iron things you have. What we do have is stone fireplaces. [1]
How it works is this: You heat the multi-hundred kg stone mass using any material you want, for us it's usually wood in some form. After the stone is hot enough, you stop wasting wood and close the chimney when the fire has burned out to prevent heat from escaping.
The stone mass will store heat and distribute it slowly and evenly over many hours, keeping everyone warm without electricity. If you want to distribute it, there are fans that operate on the radiant heat coming from the fireplace. A properly installed fireplace (central to the house) will keep a normal home toasty warm for a day or two with one proper heating cycle depending on how cold it's outside.
[1] https://www.tulikivi.com/en