I get bothered by the fact that people think Santa Claus/Father Christmas is the same as St Nick.
St. Nick is a REAL person who left money in stockings. Same as Saint Patrick, Saint David, Saint Francis etc...
Father Christmas (also interchangable with the name 'Santa Claus' hense the confusion) is a modern addition of a magical legend that lives at the north pole, flys on reindear, has magic 'elf' helpers and has litrally fuck all to do with or in common with Saint Nicholas.
He is instead based of the pre-christian eastern christmas demon Ded Moroz (Grandfather Frost, the father of the 'Ice Queen' which is the basis of Frozen and the grandfather of the famous 'Jack Frost') and wasn't even a thing in the western world until about 200 year ago.
I just see zero reason the two things get mixed up, it kind of like confusing the Easter Bunny with Jesus because they are both 'easter things', one was a real person remembered (even if your not religeous and dont believe in the son of god thing there a fair amount to say a guy called Jesus did actually exist like any Saint) and the other just a magical kids story.