A small number of katakana words have kanji associated with them despite the fact that they come from a language that has never used Chinese characters. This use of kanji is called 当て字 where the reading or meaning of kanji is forced onto a word that originally didn’t have any. These words hark back to the days before katakana become the common script for foreign words and some of them come directly from Chinese like 「珈琲」. You can still see many of these 当て字 being used today such as street signs so learning them is not a waste of time.
You can see more examples of foreign words in kanji at this page.
Kanji for Countries
Many country names also have 当て字 associated with them that are rarely used. However, in newspaper headlines, the first character of the 当て字 is often used in an effort to conserve space. For instance, newspapers use words like 「訪米（ほうべい）」 for visiting the United States or 「日韓（にっかん）」 for news related to Japan and Korea. Here is a short list of the most common
country abbreviations and their full kanji versions.