"Cut/copy and Paste" is ordinarily used in a highly pejorative sense.
But consider Mozart et al, who restated a major theme in minor mode. Good use for cut and paste, with a amall amount of editing, seems to me.
Fugue subject and counter subject: If I wish to restate the subject/counter subject in a different voice and time, copy and paste , followed by some necessary editing at least in key, is made to order.
Canon: if I wish to create a crab canon, what's the problem with copy/paste and retrograde, with suitable editing?3
Symphony: write a them for violins. Later, give it to another instrument.Made to order for a paste job
I use paste quite a lot, as I never found a point in taking a long time to re-enter a long passage one note at a time if I could repeat the whole passage in a few seconds, and then make any necessary changes.
Pasting, whether from copy or cut is a valuable tool, but I think it takes some practice and study to make good use of it.