I think it stemmed from the days when Middle English was spoken and where they would add an 's' to adverbs which was later corrupted by the Southern English who further added a further 't', probably from confusion with words that had a superlative '_st' ending (like gentle/gentlest
). I still use 'whilst' from time to time if I think a sentence with it sounds better when read aloud than a sentence using 'while'. I reckon we could do with Pooh looking on this subject since he is our resident English expert.
The difference between fiction and reality? Fiction has to make sense.