Why is some German money from the early 1900’s engraved with the word Darlehenskaffenfchein instead of Reichbanknote?
They were printed and issued primarily for use in occupied territories, during WWI
Darlehenskassenschein=State Loan Currency note.
Different backing.
Thanks a lot, for some reason I couldn’t find an answer on google.
Just out of curiosity why do only some of the s’s look like f’s.
Note that what you interpreted as an F (3 times) is actually an S.
No such thing as a Kaffenfchein…but Kassenschein, yes indeed!
If an S concludes a word, it appears as “s” rather than as the “f”-like letter that appears at the start of middle of a word.
German compounds function in some ways as independent words. Since “s” is the final letter of Darlehens, it is treated as the final letter of that word would be if it were in isolation.
The same “long s” (ſ) was used in English up to the 18th century. Look at the title page of Shakespeare’s First Folio (1623). The sixth line has “publiſhed”, and the last line has “Iſaac”, instead of “Published” and “Isaac”, but at the end of the sixth line is “Copies”, because that s ends a word. There’s only one upper-case S however, as you see in “SHAKESPEARES”.
Just don’t get into the rules for when to use the ß in German, OK? 
The Greek language has (or at least had) a similar rule. The sigma symbol, σ, is used in the middle of words. The terminal sigma, which is the symbol from which our letter s developed is used at word ends. It doesn’t look like I can display it here.
It looks like a c with a little pigtail underneath.
capital sigma - Σ
lower case sigma - σ
terminal sigma - ς
Seems to work on my computer (linux and firefox).
… And early English printing used German type, and early printing was limited by the cost of the individual slugs. So if you wanted the 's’s to go farther, you could use the ‘f’ for the purpose intended.