I used to think rather romantically about handwriting compositions, as if the pencil manuscript was some sacred work of art in itself and that the emotion of the piece was visible within the inspired strokes of the pen, etc, yadda yadda. Nowadays I am more pragmatic, particularly since I discovered how long the preparation of a score and parts takes. I only use handwritten notes for ideas if I am working at the piano or if the computer is not handy. Even then I have only ever used this for getting initial ideas and never stayed on paper for the serious writing stage for which I am completely comfortable using the laptop. Sibelius is fundamentally a time-saving tool: the note is there in the score as soon as it is written; it can be changed without having to copy the whole thing out again. Using a computer program has very little to do with the actual music, and I don't in any way endorse notions that using a laptop is somehow restricting your creativity or forcing you to write in a particular way. I write what has been planned out in my head, and the only difference to handwriting is that I choose to represent my thoughts through symbols stored as bytes rather than in ink. The play button is only the equivalent of trying an idea out on the piano, with the difference that one can hear back things that would be impossible for two hands to simulate. Again, this as often as not simply confirms I have notated correctly something I have already imagined.
I will concede that it is sometimes nice to make a handwritten presentation copy of a piece, especially if it is bound with a nice cover and used as a gift to a conductor at a première or the dedicee or something, but to do this with no mistakes takes ages and I generally don't have ages to spare. I doubt very much if anybody is going to frame my sketches or dissect them to discover my working method, although a page full of scribblings and 'bits' has a certain aesthetic charm in itself.