[[:Category:term cleanup/with sc]]
If there is no language for a given term, and it's not translingual, then what is it? In any case, though, language codes have a purpose even without linking: they mark the text as being in that language, and select the script for that language. Of course, if the script has been provided explicitly, then there is no reason to automatically determine the script, but the first point still holds. If you write Eisenbahn in a page, then is by default marked as an English word, while Eisenbahn is marked as German. You don't see a difference, but there is a difference in the underlying markup.
Just from cleaning up a few entries I've seen {term} used for "terms" in Germanic (lolwut - maybe you can make sense of it?) and used to link a term to itself as a very roundabout way to just put the pagename in italics.