How can short stories improve computer literacy? Simple really.
If you manage to encourage your child to 'write' a short story, they will almost immediately want to type it out. If they haven't already, they will soon see that keyboarding a story is more efficient than actually writing.
When you type or keyboard a long document, you are better able to read it back, move paragraphs and even correct spelling and grammar. The child is actually learning how to proof read but doesn't know the official name for it.
The next logical step is to have the hard-copy in your hands. For a child this means that he or she really created something tangible. Crossing over from the intangible to the tangible is a huge step in the learning process.
By itself, printing the document on paper is just a bonus we all enjoy. The trick is that your children realizes this too. They may even gravitate toward using the computer long before you would have.
Second, you may see what they are doing wrong, and they will learn by seeing a better way after you show them. This step-wise process will become a skill they can take on as their own.
You will have, simply by showing them how to create a short story, taught them some of the most valuable lessons life has to offer.
Soon they will be ripping off one story after another and your printer will be spewing out paper dust!