If you have a trading ship, say an T6 or bigger, and you want to break up the monotony of trading then having a Viper at a station you regularly visit would let you swap into it for a bit of combat. I'm often hundreds of ly from "home" where I have another ship stored. I also have my frEagle in my start system, it's got a few upgrades so worth selling it off, but I rarely go anywhere near LHS 3447 anymore and I've just not got around to it. I was going to move it to my new home system but actually, if I want an Eagle there it would be easier for me to just buy a new one and save the 45 minutes it would take to fly and pick it up in a stripped out Sidewinder.
That brings me to "shuttles" - if you do need to shuttle best option is to buy a Sidewinder, upgrade the FSD and remove all the excess weight. You'll get your money back on the FSD when you sell at the other end.