Earlier quoted context omitted.
There is a big difference, though. In English you would usually say grandma/grandpa and rarely qualify by on which side. In Swedish and Norwegian you always specify because the words for grandparents are inherent specific to whether they are paternal or maternal.
In everyday speech you generally do not try to be this specific, but if you wanted to (e.g. recounting family history to a doctor or talking about the relationship between your parents and granparents) you could use them to be more specific in a clear way. I agree that almost every use of farfar should be simply translated as grandmother.
Similarly in many languages using the wildcard equivalent to mean something more specific is unnatural.