Writing by hand also alters the relationship between forming a thought and recording it in words. When I write by hand I almost always form a complete sentence in my head before I write it down. When I write on the computer I tend to start typing at the onset of an idea or a sentence that I then figure out how to complete during the process of recording it.
Put another way, my process for writing sentences by hand looks like this:
THINK THINK THINK THINK WRITE WRITE WRITE WRITE
Whereas my process for writing sentences on the computer looks like this:
THINK WRITE THINK DELETE THINK WRITE THINK DELETE THINK WRITE
I find my thoughts come out cleaner by the former process. Whether they come out better is a different and still unsettled question.