[zedshaw]

You type the code in so that you get practice at typing the code in since in order to write code you have to type code in...a lot of it. If you don't then you're only learning 1/2 of writing code.

Another reason is because anyone who's good at coding learned it this way. Anyone who's bad at coding tends to just copy paste. Usually, you should copy what people who are good at something do.