for instead of because

Hi,
I’m reading an English book called “The wizard of Oz“ and I’ve got a question about using “for“ instead of “because“. In this book there is in 95% used for instead of because.
for example:
1)“I do not know where Kansas is, for I have never heard that country mentioned before.“

2)“The Land of Oz has never been civilized, for we are cut off from all the rest of the world.“

3)It was a bit of good luck to have their new comrade join the party, for soon after they had begun their journey again they came to a place where …

My question sounds if there is any difference of using for instead because. How does it sound to you (native English speaking ppl)? - more or less formal, archaic or there is no difference ?
To be honest I haven’t seen it never before.

Thank you,
David.

Using “for” instead of because sounds a bit archaic and formal, something like an old storybook. I have a friend who always says “because” but writes “for”, and I don’t understand why she does it. However, they still teach American children that “for” is one of the alternatives.

We also use “since” instead of “because”, but that sounds normal.

You can see the registers that use of “for” is normally found in in contemporary British English (per million words):

SPOKEN 0.0
FICTION 0.4
NEWSPAPER 0.7
ACADEMIC 0.6
MISC 0.5

And in American English registers:

SPOKEN 0.1
FICTION 0.4
MAGAZINE 0.2
NEWSPAPER 0.1
ACADEMIC 0.3

As far as Time magazine is concerned, that use seems to have had it’s ups and downs of popularity over the decades:

1920s 0.5
1930s 0.5
1940s 0.3
1950s 0.5
1960s 0.2
1970s 0.2
1980s 0.0
1990s 0.1
2000s 0.5

Source: view.byu.edu/

There are places where the choice of “for” just sounds right:

"Smile at us, pay us, pass us. But do not quite forget. / For we are the people of England, that never have spoken yet”.

GK Chesterton

“We are the champions, my friend… And weee’ll keep on fighting til’ the end…We are the champions, we are the champions, no time for losers, for we are the champions… of the world!”

Freddie Mercury

thank you