Lugging about a sheaf of paper is often easier than lugging about even a laptop. It doesn't need power, and you don't have to worry about the battery. I usually carry my purse so I have somewhere to stash my pens (plural, because they are gel pens and in color 0:), and I've got a book bag to lug about folders of stories. My fickle muse ensures I do not know which story I will work on once I'm sitting in the doctor's waiting room or awaiting the completion of the oil change or what have you. And it's less picky about flat surfaces though propping up the folder can be a challenge.
It's at home where things get interesting.
A laptop on a desk has to be moved to make way for handwriting. And then you need somewhere to keep it while you're writing by hand, and somewhere to stash the by-hand stuff while you're on the laptop -- hopefully the same place but that can be awkward while switching.
Must be worse working on a kitchen table or the like where everything always has to stashed away at times.