Just looking at the "inline transformations animation"... How is typing "Add the WhileExpression struct here" better or easier than copy/pasting it with keyboa

Just looking at the "inline transformations animation"... How is typing "Add the WhileExpression struct here" better or easier than copy/pasting it with keyboard and/or mouse? I want something that more quickly and directly follows my intent, not makes me play a word game. (I'm also worried it will turn into an iterative guessing game, where I have to find the right prompt to get it to do what I want, and check it for errors at every step.)