I think there's a large difference between copy-paste and what you're describing (which I'll dub 'manual transcription'). I have no formal training in learning or cognition, but I do have quite a bit of personal, anecdotal evidence to suggest that manual transcription is far more useful, from a pedagogical standpoint, than straight copy-paste.
Rather than take a boring example from my programming career I'd rather draw from my brief mathematical studies in college. In undergrad I was taking a course on Real Analysis. The course redefined, much more rigorously, certain concepts that I had understood at a much higher level--think the limit, derivatives and the Riemann Integral. Suffice it to say that these new concepts challenged my understanding of introductory Calculus, and when I was tasked with writing proofs based on the underlying concepts (e.g. neighborhoods), I struggled.
In what can only be described as frustration I decided I was going to start copying the proofs over and over. I repeatedly transcribed half a doze proofs for a few days straight (I did each one a few times each night). A strange thing happened. I began to understand the proofs. By that I mean I started to understand the intuition required to make the transition between each step of the proofs. At that point I found the material much more accessible. Reading the book was easier, the lectures made more sense, I could do homework, and consequently I could complete the exams.
I like this example because there is no copy-paste alternative. I had to engage with the material, but I chose to engage at a very mechanical level. Still, there was something about the process of reading and writing that aided in understanding the material.
I don't believe you can get that with copy-paste unless you find some other way to engage with the code.
I'm very interested in whether or not manual transcription is pedagogically beneficial.
I personally write a lot. I certainly find it useful to do that.
However, I would not normally recommend Zed Shaw "Learn Code the Hard Way" type of method of writing out over and over again. I think it probably works and you can do it yourself, but I think it's quite inefficient. I don't need to type 10 PRINT "HELLO" 20 GOTO 10 more than once to get a good sense of what's going on.
I think you most of all benefit here from the time you're forced to put in. If you can understand nothing, there's really no other sensible thing that allows you to concentrate for the time you need to make decent progress.
However, I don't think this means transcription is pedagogically ideal. IMHO building something for yourself is more effective; getting expert tuition is more effective: in terms of time spent vs benefit received.
Rather than take a boring example from my programming career I'd rather draw from my brief mathematical studies in college. In undergrad I was taking a course on Real Analysis. The course redefined, much more rigorously, certain concepts that I had understood at a much higher level--think the limit, derivatives and the Riemann Integral. Suffice it to say that these new concepts challenged my understanding of introductory Calculus, and when I was tasked with writing proofs based on the underlying concepts (e.g. neighborhoods), I struggled.
In what can only be described as frustration I decided I was going to start copying the proofs over and over. I repeatedly transcribed half a doze proofs for a few days straight (I did each one a few times each night). A strange thing happened. I began to understand the proofs. By that I mean I started to understand the intuition required to make the transition between each step of the proofs. At that point I found the material much more accessible. Reading the book was easier, the lectures made more sense, I could do homework, and consequently I could complete the exams.
I like this example because there is no copy-paste alternative. I had to engage with the material, but I chose to engage at a very mechanical level. Still, there was something about the process of reading and writing that aided in understanding the material.
I don't believe you can get that with copy-paste unless you find some other way to engage with the code.