I understand the controversy, In my experience, both statements; 'typing it does nothing' and 'typing it is everything' are accurate. Just for different people.

In a similar way, some people don't see music until they play it, some see it before it is played. I really don't know what it is that creates the difference.

For me, doing the typing (or writing in my notebook) really connects the knowledge somewhere in my head that is harder to erase/lose than just reading or seeing it. I discovered in college that I could look at a homework problem and solve it but later in an exam couldn't bring back all the finer points of solving it, unless I had actually written down my solution. Very strange but a good thing to know about oneself.